SB 3.20.1
saunaka uvaca
mahim pratistham adhyasya
saute svayambhuvo manuh
kany anvatisthad dvarani
margayavara-janmanam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Sri Saunaka inquired: O Suta Gosvami, after the earth was again situated in its orbit, what did Svayambhuva Manu do to show the path of liberation to persons who were to take birth later on?
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The appearance of the Lord as the first boar incarnation occurred during the time of Svayambhuva Manu, whereas the present age is in the period of Vaivasvata Manu. Each Manu’s period lasts seventy-two times the cycle of four ages, and one cycle of ages equals 4,320,000 solar years. Thus 4,320,000 × 72 solar years is the reign of one Manu. In each Manu’s period there are many changes in many ways, and there are fourteen Manus within one day of Brahma. It is understood here that Manu creates scriptural regulations for the salvation of the conditioned souls, who come to the material world for material enjoyment. The Lord is so kind that any soul who wants to enjoy in this material world is given full facility for enjoyment and at the same time he is shown the path of salvation. Saunaka Rsi, therefore, inquired from Suta Gosvami: “What did Svayambhuva Manu do after the reinstatement of the earth in its orbital situation?”