The Book of Moses is largely just a retelling of the earlier part of Genesis, but with some added details. Smith was probably holding to the traditional (but almost certainly inaccurate) view that Moses was the author of the Torah/Pentateuch. There's something in it about Moses not wanting anyone to know the extra information, even though most of it isn't all that different from what's in the actual Bible. Satan plays a much larger role in Joe's retelling, having become an enemy of God when the big guy chose Lucifer's brother Jesus to redeem mankind instead of him. So he goes on to mess with mankind, possessing the snake that convinces Adam and Eve to eat the forbidden fruit, and making pacts with Cain and his descendant Lamech. We also learn that God told Adam about both Jesus and water baptism. (Speaking of which, I was wrong last week about Smith originally favoring infant baptism; he was actually always against it.) Joe Smith apparently hadn't yet come up with the idea of the Garden of Eden being in Missouri, or at least didn't choose to mention it in this book. He does, however, tell more about Enoch, whom God chose as a prophet and preacher, but Enoch objected due to being "slow of speech." Gee, that sounds familiar. But anyway, Enoch becomes a rather successful religious leader, moving mountains and making rivers change course with his words, as well as founding the city of Zion on some land that magically rose out of the sea. Like some Southern towns, Zion was whites-only, since, in the Mormon universe, darker skin indicates disobedience to God. Eventually, the city itself was taken up to Heaven, but another city of Zion would be founded later.
The Book of Abraham has a rather interesting back story. Smith and some friends of his bought some Egyptian papyri from a travelling exhibit. They turned out to actually be about funeral rites, but Joe claimed that they were written by Abraham, and told some details about God even crazier than what he'd come up with before. The pages had illustrations, but Smith completely misinterpreted them, taking a picture of embalming as an illustration of ritual human sacrifice. According to Joseph's supposed translation, God lives on a planet orbiting the star Kolob, and one of God's years is measured by one revolution of this planet around the star. He was hardly the only person in history to hold to the "God is an alien" idea (I'll have another post on that in the future), but it's really pretty far removed from the more traditional view of the Christian God that the Book of Mormon promotes. The book also shows Smith toying with polytheism, another radical departure from his earlier work. But the blatant racism is still there, with a mention that the first Pharaoh of Egypt couldn't be a priest because he was black.