(Genesis 1:26) The God said, "Let us make humanity in our own image, in the likeness of ourselves, and let them be masters of the fish of the sea, the birds of heaven, the cattle, all the wild beasts and all the reptiles that crawl upon the earth."
(1: 27) The God created humanity in the image of themselves, In the image of the Gods they created them, Male and female they created them.
(1:28) The God blessed them, saying to them, "Be fruitful, multiply, fill the earth and conquer it. Be masters of the fish of the sea, the birds of heaven and all living animals on the earth."
Now this is before God starts his experiment in Eden. These people weren't created from the dust or from a rib, they were created and told to multiply, and be masters of the earth. The next chapter is where Yahweh begins the garden.
(Gen 2:7) God fashioned a man of dust from the soil. Then he breathed into his nostrils a breath of life, and thus the man became a living being.
(2:8) God planted a garden in Eden which is in the east, and there he put the man he had fashioned.
(2:9) God caused to spring up from the soil every kind of tree, enticing to look at and good to eat, with the tree of life and the tree of the knowledge of good and evil in the middle of the garden.
(2:15)God took the man and settled him in the garden of Eden to cultivate and take care of it.
In my interpretation of the book, there is another group of god made beings outside of the creation experiment of Eden. Living, having babies, etc. Now on Cain:
(4:16) Cain left the presence of God and settled in the land of Nod, east of Eden.
I don't really understand how one can leave the presence of an omnipresent God but anyways, He settled in the land of Nod where there were already people. Did Adam and Eve populate an entire other land before Cain left the presence of God?
I believe that there were another set of peoples, that Cain left God's experiment and went to live with these other people. Where he met his wife, had a son then founded his own city.