Leaving this OP strictly to the Bible, how many people? Was it just Adam and Eve and the rest of the population spawned from those two? Or were other people created and we just not know about it?
If you’re going strictly by the Bible then ultimately, he created all of them.
Genesis II. 7: “Then the Lord God formed man of the dust ofthe ground, and breathed into his nostrils the breath of life; and man became a living soul.”
Genesis II, 21 and 22: “And the Lord God caused a deep sleep to fall upon the man, and he slept; and He took one of his ribs, and closed up the place with flesh instead thereof. And the rib, which the Lord God had taken from the man, made He a woman, and brought her unto the Man.”
According to the Bible, those are the only two homo sapiens that God directly created.
As with many aspects of the bible, there is not total agreement on this. In Genesis I, reference is made to creating men, but no reference is made to how many. However, they are told to “be fruitful and increase in number,” suggesting that however many there were, there would soon be many more. See Genesis 1:26-1:28.
In Genesis II, however, only one man, Adam, is described as having been created. No being fruitful for him. 
Woman didn’t come along until God decided, “It is not good for man to be alone.” He then created Eve from Adam’s rib. Nothing was said about being “fruitful” at this point; Eve was created to be Adam’s “helper.” Here, it looks as though only the two of them were created, and they weren’t exactly lords over the Earth.
See this Staff Report (Who wrote the Bible? (Part 1)) for information on why the two creation stories differ.
After the Fall, they had children the normal way. Only Cain and Abel were mentioned at this point, so we assume these are the only four people on the Earth. After Cain murdered Abel, he went to Nod. Here is the next mention of another person: Cain’s wife. Where did she come from? Was she also Cain’s sister? We don’t know.
Some people think that God must have created more than just Adam and Eve, but they weren’t mentioned after Genesis I. Other people think only Adam and Eve were created and they inbreeded. I don’t know which is right, if either. There’s no way to extrapolate this from the Bible.
-Loopus
Don’t forget about the apocryphal Lillith (Adam’s “first wife”). I think Cecil might have even written about her some time ago.
Not Cecil, but a Staff Report.
Genesis 4:14-15
14 Behold, thou hast driven me out this day from the face of the earth; and from thy face shall I be hid; and I shall be a fugitive and a vagabond in the earth; and it shall come to pass, [that] every one that findeth me shall slay me.
15 And the LORD said unto him, Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And the LORD set a mark upon Cain, lest any finding him should kill him.
There were more people than just Cain’s wife out there. Who exactly they were isn’t explained. However, they can be killed 7 times, since that would be the punishment for killing Cain once.
Maybe they were cat people. Those cat people that had only died once or not at all would still be a threat to Cain.
It strikes me as strange that the folks responding to the staff enquiry didn’t note that the Alphabet of Ben-Sirah, above and beyond being controversial, was most likely a Christian forgery.
Cheers,