Use a sticker maker, stick glue, or rubber cement to secure the template to sheet metal.
Cut the designs out with a saw. This is a good project to practice sawing skills because no one leaf is exactly like another. Besides, the leaves will be on different sides of the face so cutting differences will not be as noticeable.
If you REALLY do not want to saw the leaves out, punch holes corresponding to the size of the inner curve between each leaf section using a 7 Holes Metal Punch Kit. Use shears to cut around the leaf shape and into the holes.