The Chronology having been brought up to Noah's days, the History takes us back (not forward).
men. sing, with art.. the man Adam. See App-14.
earth. Hebrew. h'adamah, ground.
them: i.e. to Adam and Eve, as in Genesis 1:27 and Genesis 5:2.
Related Commentaries of Genesis 6:1
Genesis 6:1
1 And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them,