When I was a kid, I wasn't good at making paper airplanes, but I loved making paper boats and put them to float on the water. I know that there must be a million instructions of how to fold paper boats on the internet, but I decided to write mine anyways.
All you need is a piece of paper, I used regular printing paper and my little advice is for you to color at least the bottom of the boats with crayon, the wax of the crayon will protect the boat from soaking up the water so fast.
I hope the instructions were helpful. Have fun!