Genesis 8 describes the floodwaters receding and Noah leaving the Ark.
Genesis 6 introduces the corruption of the world, Noah’s righteousness, and the instructions for building the ark. Genesis 7 then describes the entry into the ark, the flood, and the rising waters. Genesis 8 turns to the recession of the waters, the birds Noah sends out, and the eventual drying of the earth.
At the end of the chapter, God tells Noah to leave the ark with his family and all the animals. Noah then builds an altar and offers burnt offerings. Genesis 9 follows with the covenant and rainbow sign, placing the covenant immediately after the ark narrative.
Chapter divisions were added to biblical manuscripts long after the text was composed. They are useful for locating passages, but they are not part of the original continuous wording of Genesis. The flood account itself spans Genesis chapters 6 through 9.