The animals come, Noah and his family enter the ark, God shuts the door, it rains for 40 days causing a flood to cover even the highest mountains and everything that wasn’t in the ark dies, except the fish, though some versions even mention the things that swim died too, so not sure what to make of that.
It does strike me strange that Noah’s sons were 100 years old – but had no children of their own? Was that God’s plan to limit the number of occupants of the ark? Did they marry late just before the flood? Perhaps Noah had grand-children but they were not saved.
Many commentaries make much of the symbolism of 40 as in 40 days of testing and trial. Also, a natural question arises as to where did all the water come from. One commentary stated that the oceans floors could have been raised and then the amount of water would be sufficient, and also that the flood may have included the water locked up in the polar ice caps. There is also scientific evidence for oceans of water under the earth's mantle. Well, if one believes in God, we know He could have turned dry land into water as easily as water into wine.
I speculate that those who were accustomed to seeing Noah’s ark gradually taking shape probably thought he was a nut case but what do you think they were thinking when the animals just started appearing out of nowhere and then march into the ark? Atheists today are no different than the scoffers and nay-sayers in Noah’s time. They laugh at us who believe in the literal accuracy and inerrancy of the Bible and all we can do is pray for a change of their heart – a gift of faith – as one day whether alive in this world or from the grave, they will witness the destruction and rebirth of the universe. So, who are we going to be, a Noah or a son of Cain?