Ways of preparation are different, but I will show my own:
1. Tear on small pieces any paper and presoak in water for days.
2. Crush it in a blender.
3. Wring out excess water and spread in a bowl.
4. For production of paper add only PVA glue;
5. Mix everything with hands.
6. Store in bags in cold.
7. Mold whatever you want! It dries for 2-3 days if it's thin layer (thicker layers it is better to increase gradually).