How did adam and eve figure out the sex thing?

So if Cain and Abel were their sons, one of Adam's and one of satan's, did it not say some where in most translations that they went out and took wives?
Where did the wives come from?
If Adam and Eve were the first humans where did the wives come from?
Did they interbred with Eve?
How did they multiply?

Pre- Presbyterian church that Trump's mom belonged to, believe that Cain & Abel were twins, but there is the anomaly that Cain was of a 'red disposition' and Abel was not; which does suggest that one was the seed of hasatan and one was the seed of Adam, which goes toward the children of Cain.

If that is the case, they would have multiplied with the children of one another, and would explain much.

The Serpent beguiled Eve. So in my mind he seduced her. Alot of people just dont think. But Thats what I think.

agreed on all counts, @jbullockhubbard . He definitely beguiled her and most likely seduced her; and people def don't think in these days of deception, chaos, and confusion. (Might I add, deliberate on all 3 counts?)