RVT110 is a small double cap domed rivet with an antique copper finish.  Cap diameter is 1/4″, and the post length is also 1/4″ so these are small and best for thin leathers.  Punch holes in the leather, push the post through, place the cap on the post, and give it a tap.  To keep the cap from flattening when you whack it use this tool right here.  RVT-110, pack of 50 for $8, or get 100 for $12, and both prices include USA shipping.  Right to your door.  Or mailbox.  You get the picture.