As a former preschool teacher, I have a recipe for you. Mind you, it doesn't make "perfect" paper but is fun and easy.
You'll need: a metal mesh strainer, tissues or toilet paper, water, a sponge, a bowl
-Start by tearing up the toilet paper or tissue in the bowl
-Pour a little water in and stir it up.
-Pour the mixture into the sieve and press with the sponge
-Gently take out the matted "paper" and allow to dry
Variation: Put food coloring or glitter in the mixture for fun!
Note: This recipe was used to teach the concept of recycling, so, technically, it's not "making" paper from scratch. But, fun anyway!!