The first purusa is Karanodakasayi Visnu, the second purusa is Garbhodakasayi Visnu, and the third purusa is Ksirodakasayi Visnu

Expressions researched:
"The first puruṣa is Kāraṇodakaśāyī Viṣṇu, the second puruṣa is Garbhodakaśāyī Viṣṇu, and the third puruṣa is Kṣīrodakaśāyī Viṣṇu"

Srimad-Bhagavatam

SB Canto 3

The first puruṣa is Kāraṇodakaśāyī Viṣṇu, the second puruṣa is Garbhodakaśāyī Viṣṇu, and the third puruṣa is Kṣīrodakaśāyī Viṣṇu, in whom is contemplated the virāṭ-puruṣa.

SB 3.7.22, Translation and Purport

The puruṣa incarnation lying on the Causal Ocean is called the original puruṣa in the material creations, and in His virāṭ form, in whom all the planets and their inhabitants live, He has many thousands of legs and hands.

The first puruṣa is Kāraṇodakaśāyī Viṣṇu, the second puruṣa is Garbhodakaśāyī Viṣṇu, and the third puruṣa is Kṣīrodakaśāyī Viṣṇu, in whom is contemplated the virāṭ-puruṣa, the gigantic form in which all the planets with their different developments and inhabitants are floating.