After hearing about the prayers of Brahma and the blessings he received from the Lord, Vidhura wanted to know about the subsequent creations of Brahma: “Śrī Vidura said: O great sage, please let me know how Brahmā, the grandfather of the planetary inhabitants, created the bodies of the living entities from his own body and mind after the disappearance of the Supreme Personality of Godhead.” (SB 3.10.1)
Maitreya starts his answer by describing how after meeting the Lord, Brahma engaged in penances for 100 celestial years more before starting the creation. In his purport, Srila Prabhupada explains that he was not engaged in meditation, like in the period of 1000 celestial years before meeting the Lord, but in direct devotional service to the Lord. After this period, his concentration was broken by strong cosmic winds that made both the Garbhodaka Ocean and the universal lotus tremble. The lower part of the universe, where the lower planets as well as Bhu-mandala were supposed to be was thus completely flooded. Being put in such an awkward situation, Brahma’s attention returned to his service of creating the universe.
Srimad Bhagavatam #22: Cosmic time in the Vedas