Paper is made from any bashed up fibres. The fibre soup is dried in thin layers to make paper. Old paper can be remade into new paper. You can see how here. The pulp can be made without a blender, just soak, mash, soak and mash (you can use a pestle and mortar) at intervals over 24hrs.

Cardboard is thick paper, sometimes with extra reinforcing ribs inside. Cardboard cuts, folds and joins easily. Score a shallow cut along the surface of the cardboard first to ensure it bends where you want it to.