Here's what God says to Noah and his family after the flood waters have receded. "Be fruitful and multiply." "You have dominion over every living thing." "Every living thing is appropriate for you to eat, but don't eat blood." "I promise never to kill everybody with a flood again and as a sign I give you the rainbow." "Don't kill each other."
Noah and his three boys are said to be the ancestors of all humanity. The youngest, Ham, sees his old man naked after Noah has been on a bender. This pisses Noah off so much that he curses Ham, more particulraly Ham's boy Canaan, and declares that Canaan will be servant to Shem and Japeth. I reckon this curse came in real handy when the Hebrews were exterminating the Canaanites later on. Man, how touchy was Noah? So somebody saw his shriveled up old frame. Big whoop.
Could Noah have been the male progenitor of all humanity? While it would have been possible, with luck, to reproduce exponentially, there is no evidence of this in archaeology or our genes. And there was no planetary flood, either. Maybe there was a spectacular local flood that inspired this and similar stories, but let's just admit that it's a myth. It's a slanderous myth at that. It makes God out to be a mass murderer and the author of evil in the world. Maybe that's how the authors saw God.
Chapter 10 gives some tidbits about the descendants of Shem, Ham and Japeth and states that the nations were divided up "every one according to his language". (Remember this when we get to the Tower of Babel.) These tidbits are unremarkable except for the exploits of Nimrod who was a mighty hunter and who built a lot of cities. This probably was meant to explain, as in a "Just So Story", the relationships of the various peoples known to the authors. Does it matter? No. Will anyone be edified spiritually by this information? Doubt it.
Chapter 11 contains the myth of the Tower of Babel and the warthful dispersion theory of linguistics. God does this because He wants to prevent humans from progressing. This seems to be a major concern of the God of the early Old Testament. Keep humans from the Tree of Life? Check. Prevent humans from attaining too much technical know how? Check. The rest of the chapter is concerned with getting from Shem to Abram and his immediate family.
Does it matter if any of this is true or not? Not a bit. Take it or leave it. It's just not believable. The first eleven chapters strike me as a hodge podge of legends thrown together for no particular reason than that folks knew them and would have expected their own history to fit into the familiar narrative. It's only when you get to Abram that the stories have any kind of narrative continuity, so I reckon you could just as well ignore the first eleven chapters and start with Genesis 12. You won't have missed anything, and you won't have started out straining credulity beyond the breaking point.