You should always stamp leather on a firm surface, as you'll need to use a considerable amount of force to get the stamps to stick. It's a good idea to place a piece of hardwood down on a flat surface. Stamp the leather on the hardboard. You can purchase blocks of hardwood at most department stores. Take your leather stamp. Place the stamp down where you want the image or letter to appear on your leather. Hold it in place with one hand. You will need to buy leather stamps. You can buy them online or at some craft shops. Use your other hand to hammer down on the stamp. This will secure the image or letter into the leather. Give the stamp a few firm strikes with the hammer until the image or letter transfers. Once your image or letter has transferred, repeat the process again with the second image or letter. Press the stamp down where you want it on the leather and then give the stamp a few firm strikes with a hammer to transfer the image.

Summary:
Place the leather on a firm surface. Position your stamp on the leather. Use a hammer to press the stamp on the leather. Repeat the process to complete your design.