This keychain is not only stylish, but useful too!
Cut the piece of leather into three, 3mm strips (or slimmer/larger if you wish). Put the piece of leather through the key ring, and fold it over so the edges line up.
Using an X-ACTO knife, or scissors, cut a hole a little below the keyring, for the first rivet. Make sure to cut all the way through both pieces of leather.
Put the “bottom” piece of the rivet through the back of the keychain, all the way through the top piece of leather. Place the “top” of the rivet onto the bottom, and snap into place. Make sure its secure.
Add the assorted studs to only the front piece of leather. Stick them through the leather and use the screwdriver to press the prongs into the back to hold it in place.
When you get to the end of the keychain, repeat step #3.