This creation is very appropriately compared to clouds. Clouds are created or situated in the sky, and when they are displaced they remain in the same sky without manifestation. Similarly, the whole creation is made by the Supreme Personality of Godhead in His form of Brahmā, it is maintained by Him in the form of Viṣṇu, and it is destroyed by Him in the form of Rudra, or Śiva, all in due course. This creation, maintenance and destruction are nicely explained in the Bhagavad-gītā (8.19-20) as follows:
bhūta-grāmaḥ sa evāyaṁ
bhūtvā bhūtvā pralīyate
rātry-āgame 'vaśaḥ pārtha
prabhavaty ahar-āgame
paras tasmāt tu bhāvo 'nyo
'vyakto 'vyaktāt sanātanaḥ
yaḥ sa sarveṣu bhūteṣu
naśyatsu na vinaśyati
The nature of the material world is that it is first created very nicely, then it develops very nicely and stays for a great number of years (even beyond the calculation of the greatest mathematician), but after that it is again destroyed during the night of Brahmā, without any resistance, and at the end of the night of Brahmā it is again manifested as a creation to follow the same principles of maintenance and destruction.
(Srimad Bhagavatam----2:10:43----purport).

There are three different types of creation, called mahā-kalpa, vikalpa and kalpa. In the mahā-kalpa the Lord assumes the first puruṣa incarnation as Kāraṇodakaśāyī Viṣṇu with all the potencies of the mahat-tattva and the sixteen principles of creative matter and instruments. The creative instruments are eleven, the ingredients are five, and all of them are products of mahat, or materialistic ego. These creations by the Lord in His feature of Kāraṇodakaśāyī Viṣṇu are called mahā-kalpa. The creation of Brahmā and dispersion of the material ingredients are called vikalpa, and the creation by Brahmā in each day of his life is called kalpa. Therefore each day of Brahmā is called a kalpa, and there are thirty kalpas in terms of Brahmā's days.
(Srimad Bhagavatam----2:10:46----purport).

The four yugas are calculated in terms of the heavenly calendars and accordingly are twelve thousand years in terms of the heavenly planets. This is called a divya-yuga, and one thousand divya-yugas make one day of Brahmā. The creation during the day of Brahmā is called kalpa, and the creation of Brahmā is called vikalpa.
(Srimad Bhagavatam----2:10:46----purport).

Therefore the thirty kalpas of Brahmā are: (1) Śveta-kalpa, (2) Nīlalohita, (3) Vāmadeva, (4) Gāthāntara, (5) Raurava, (6) Prāṇa, (7) Bṛhat-kalpa, (8) Kandarpa, (9) Sadyotha, (10) Īśāna, (11) Dhyāna, (12) Sārasvata, (13) Udāna, (14) Garuḍa, (15) Kaurma, (16) Nārasiṁha, (17) Samādhi, (18) Āgneya, (19) Viṣṇuja, (20) Saura, (21) Soma-kalpa, (22) Bhāvana, (23) Supuma, (24) Vaikuṇṭha, (25) Arciṣa, (26) Valī-kalpa, (27) Vairāja, (28) Gaurī-kalpa, (29) Māheśvara, (30) Paitṛ-kalpa.
These are Brahmā's days only, and he has to live months and years up to one hundred, so we can just imagine how many creations there are in kalpas only. Then again there are vikalpas, which are generated by the breathing of Mahā-Viṣṇu, as stated in the Brahma-saṁhitā (yasyaika-niśvasita-kālam athāvalambya jīvanti loma-vilajā jagadaṇḍa-nāthāḥ (Bs. 5.48)). TheBrahmās live only during the breathing period of Mahā-Viṣṇu. So the exhaling and inhaling of Viṣṇu are mahā-kalpas, and all these are due to the Supreme Personality of Godhead, for no one else is the master of all creations.
(Srimad Bhagavatam----2:10:46----purport).

The present duration of a kalpa of Brahmā is called the Varāha-kalpa or Śvetavarāha-kalpa because the incarnation of the Lord as Varāha took place during the creation of Brahmā, who was born on the lotus coming out of the abdomen of Viṣṇu. Therefore this Varāha-kalpa is also called Pādma-kalpa, and this is testified by ācāryas like Jīva Gosvāmī as well as Viśvanātha Cakravartī Ṭhākura in pursuance of the first commentator, Svāmī Śrīdhara. So there is no contradiction between the Varāha and the Pādma-kalpa of Brahmā.
(Srimad Bhagavatam----2:10:47----purport).

Lord Kṛṣṇa and Balarāma are not two different Personalities of Godhead. God is one without a second, but He expands Himself in many forms without their being separate from one another. They are all plenary expansions. The immediate expansion of Lord Kṛṣṇa is Baladeva, and Brahmā, born from the lotus flower from Garbhodakaśāyī Viṣṇu, is an expansion of Baladeva. This indicates that Kṛṣṇa and Baladeva are not subjected to the regulations of the universe; on the contrary, the whole universe is under Their subjugation. They appeared at the request ofBrahmā to liberate the burden of the world, and They relieved the world by many superhuman activities so that everyone became happy and prosperous.
(Srimad Bhagavatam----3:1:26----purport).

For the creation, maintenance and dissolution of the cosmic manifestations there are three incarnations: Brahmā, Viṣṇu and Maheśvara (Lord Śiva). They are the controllers or masters of the three modes of material nature, which cause the phenomenal manifestation. Viṣṇu is the master of the mode of goodness, Brahmā is the master of the mode of passion, and Maheśvara is the master of the mode of ignorance. There are different kinds of devotees according to the modes of nature. Persons in the mode of goodness worship Lord Viṣṇu, those in the mode of passion worship Lord Brahmā, and those in the mode of ignorance worship Lord Śiva. All three of these deities are incarnations of the Supreme Lord Kṛṣṇa because He is the original Supreme Personality of Godhead. The demigods directly refer to the lotus feet of the Supreme Lord and not to the different incarnations. The incarnation of Viṣṇu in the material world is, however, directly worshiped by the demigods. It is learned from various scriptures that the demigods approach Lord Viṣṇu in the ocean of milk and submit their grievances whenever there is some difficulty in the administration of universal affairs. Although they are incarnations of the Lord, Lord Brahmā and Lord Śiva worship Lord Viṣṇu, and thus they are also counted amongst the demigods and not as the Supreme Personality of Godhead. Persons who worship Lord Viṣṇu are called demigods, and persons who do not do so are called asuras, or demons. Viṣṇu always takes the part of the demigods, but Brahmā and Śiva sometimes take the side of the demons; it is not that they become one in interest with them, but sometimes they do something in order to gain control over the demons.
(Srimad Bhagavatam----3:5:43----purport).

The three deities Brahmā, Viṣṇu and Maheśvara (Śiva), the executive heads of the three modes of material nature (passion, goodness and ignorance), are all generated from Garbhodakaśāyī Viṣṇu, who is described herein by Brahmā. From the Kṣīrodakaśāyī Viṣṇu, many Viṣṇu incarnations expand at different ages in the duration of the cosmic manifestation. They are expanded only for the transcendental happiness of the pure devotees. The incarnations of Viṣṇu, who appear at different ages and times, are never to be compared to the conditioned souls. The viṣṇu-tattvas are not to be compared to deities like Brahmā and Śiva, nor are they on the same level. Anyone who compares them is called a pāṣaṇḍī, or infidel. Tamasaḥ, mentioned herein, is the material nature, and the spiritual nature has a completely separate existence from tamaḥ. Therefore, spiritual nature is called avabodha-rasa, or avarodha-rasa. Avarodha means "that which completely nullifies." In the Transcendence there is no chance of material contact by any means. Brahmā is the first living being, and therefore he mentions his birth from the lotus flower generated from the abdomen of Garbhodakaśāyī Viṣṇu.
(Srimad Bhagavatam----3:9:2----purport).

A pure devotee of the Lord like Brahmā and persons in his disciplic succession are always unhappy to see the perplexities of the conditioned souls, who are suffering the onslaughts of the threefold miseries which pertain to the body and mind, to the disturbances of material nature, and to many other such material disadvantages. Not knowing adequate measures for relieving such difficulties, suffering persons sometimes pose themselves as leaders of the people, and the unfortunate followers are put into further disadvantages under such so-called leadership. This is like a blind man's leading another blind man to fall into a ditch. Therefore, unless the devotees of the Lord take pity on them and teach them the right path, their lives are hopeless failures. The devotees of the Lord who voluntarily take the responsibility of raising the foolish materialistic sense enjoyers are as confidential to the Lord as Lord Brahmā.
(Srimad Bhagavatam----3:9:8----purport).

In the material creation Brahmā has to create all kinds of living entities with bodies suitable to their material conditions. Brahmā wants to be protected by the Lord because he has to contact many, many vicious living entities. An ordinary brāhmaṇa may fall from the brahma-tejas, or the power of brahminical excellence, due to his association with many fallen, conditioned souls. Brahmā, as the supermost brāhmaṇa, is afraid of such a falldown, and therefore he prays to the Lord for protection.
(Srimad Bhagavatam----3:9:24----purport).

Brahmā's enlightenment in knowledge was due to the Lord sitting within his heart. After being created, Brahmā could not ascertain the source of his appearance, but after penance and mental concentration he could see the source of his birth, and thus he became enlightened through his heart. The spiritual master outside and the spiritual master within are both representations of the Lord. Unless one has contact with such bona fide representations, one cannot claim to be a spiritual master. Lord Brahmā had no opportunity to take the help of a spiritual master from outside because at that time Brahmā himself was the only creature in the universe. Therefore, on becoming satisfied by the prayers of Brahmā, the Lord enlightened him about everything from within.
(Srimad Bhagavatam----3:9:26----purport).

The devastating water was so fearful that even Brahmā was perturbed at its appearance and became very anxious about how to situate the different planetary systems in outer space to accommodate the different kinds of living entities, such as the human beings, those lower than the human beings, and the superhuman beings. All the planets in the universe are situated according to the different grades of living entities under the influence of the modes of material nature. There are three modes of material nature, and when they are mixed with one another they become nine. When the nine are mixed they become eighty-one, and the eighty-one also become mixed, and thus we ultimately do not know how the delusion increases and increases. Lord Brahmā had to accommodate different places and situations for the requisite bodies of the conditioned souls. The task was meant only for Brahmā, and no one in the universe can even understand how difficult it was. But by the grace of the Lord, Brahmā was able to execute the tremendous task so perfectly that everyone is amazed to see the workmanship of the vidhātā, or the regulator.
(Srimad Bhagavatam----3:9:27-28----purport).

The seeds of all the planets in the universe were impregnated in the lotus on which Brahmā was situated. All the planets were already generated by the Lord, and all the living entities were also born in Brahmā. The material world and the living entities were all already generated in seedling forms by the Supreme Personality of Godhead, and Brahmāwas to disseminate the same seedlings all over the universe. The real creation is therefore called sarga, and, later on, the manifestation by Brahmā is called visarga.
(Srimad Bhagavatam----3:10:7----purport).

Every living being lives for one hundred years in terms of the times in different planets for different entities. These one hundred years of life are not equal in every case. The longest duration of one hundred years belongs to Brahmā, but although the life of Brahmā is very long, it expires in the course of time. Brahmā is also afraid of his death, and thus he performs devotional service to the Lord, just to release himself from the clutches of illusory energy. Animals, of course, have no sense of responsibility, but even humans, who have developed a sense of responsibility, while away their valuable time without engaging in devotional service to the Lord; they live merrily, unafraid of impending death. This is the madness of human society. The madman has no responsibility in life. Similarly, a human being who does not develop a sense of responsibility before he dies is no better than the madman who tries to enjoy material life very happily without concern for the future. It is necessary that every human being be responsible in preparing himself for the next life, even if he has a duration of life like that of Brahmā, the greatest of all living creatures within the universe.
(Srimad Bhagavatam----3:11:33----purport).

According to Padma Purāṇa (Prabhāsa-khaṇḍa), in thirty days of Brahmā many kalpas take place, such as the Varāha-kalpa and Pitṛ-kalpa. Thirty days make one month of Brahmā, beginning from the full moon to the disappearance of the moon. Twelve such months complete one year, and fifty years complete one parārdha, or one half the duration of the life ofBrahmā. The Śveta-varāha appearance of the Lord is the first birthday of Brahmā. The birth date of Brahmā is in the month of March, according to Hindu astronomical calculation. This statement is reproduced from the explanation of Śrīla Viśvanātha Cakravartī Ṭhākura.
(Srimad Bhagavatam----3:11:35----purport).

The great sage Maitreya has given a considerable description of the time of different dimensions, beginning from the atom up to the duration of the life of Brahmā. Now he attempts to give some idea of the time of the unlimited Personality of Godhead. He just gives a hint of His unlimited time by the standard of the life of Brahmā. The entire duration of the life of Brahmā is calculated to be less than a second of the Lord's time, and it is explained in the Brahma-saṁhitā (5.48) as follows:
yasyaika-niśvasita-kālam athāvalambya
jīvanti loma-vilajā jagad-aṇḍa-nāthāḥ
viṣṇur mahān sa iha yasya kalā-viśeṣo
govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
"I worship Govinda, the Supreme Personality of Godhead, the cause of all causes, whose plenary portion is Mahā-Viṣṇu. All the heads of the innumerable universes (the Brahmās) live only by taking shelter of the time occupied by one of His breaths." The impersonalists do not believe in the form of the Lord, and thus they would hardly believe in the Lord's sleeping. Their idea is obtained by a poor fund of knowledge; they calculate everything in terms of man's capacity. They think that the existence of the Supreme is just the opposite of active human existence; because the human being has senses, the Supreme must be without sense perception; because the human being has a form, the Supreme must be formless; and because the human being sleeps, the Supreme must not sleep. Śrīmad-Bhāgavatam, however, does not agree with such impersonalists. It is clearly stated herein that the Supreme Lord rests in yoga-nidrā, as previously discussed. And because He sleeps, naturally He must breathe, and the Brahma-saṁhitā confirms that within His breathing period innumerable Brahmās take birth and die.
(Srimad Bhagavatam----3:11:38----purport).