Noah, You need to build an ark and on that ark take your wife, your son's and your son's wives and two of every kind of clean animal and one of every kind of dirty animals.
God doesn't like the way people are treating each other so since Noah isn't a sinner he tells him to build an ark so that when God floods the Earth Noah and his family don't die along with everyone else.
Noah builds an ark and is ready to gather animals.
Noah gets all the required animals.
People are drowning.
The bird was sent out to find a place to land and if it didn't return it had found a place but the bird returned to the ark with an alive leave in its mouth so Noah waited 7 more days to wait for the water to clear up.
This is God's bow in the sky to represent his promise that he won't flood the Earth to kill the sinners.