Cut hearts from of pieces of construction paper. The hearts can be as large or small as you wish, so long as the finished size fits onto the transparent contact paper. Use a hole punch to create a starting point for removing the center of the heart.
Remove the backing from the transparent contact paper to expose the adhesive side. Lay the contact paper smooth side down on a table, and position the red construction paper hearts on top of it. Make sure that the contact paper extends around the outside of the heart.