First, you will have to select the size of the paper that you want to use for the print. You can use a piece of cardboard that should be of the same size or a bit smaller.
Take materials with different shapes and textures, which you can use to create a background for your printing plate. Here, you can use glue to attach the materials to the surface of the plate.
Consider shellacking the entire printing plate. This will make your printing plate easy to wash off and use multiple times.
Cover the plate with paint and place the printing plate on a sheet of paper. Use a spoon or rolling pin to press down on the plate. In order to get the most even print possible, try to push with the same amount of pressure on all parts of the plate.
Allow your print to dry and wash off your plate to store for future use.