I found a number of websites that showed tutorials on how to use these snap type clasps and wanted to learn how they work. U Handbags tutorial is my favorite.
The clasps come in either sewing on or glued in. I think the glued ones have a much more professionally finished look. I ordered a few from Bagsupplier on Etsy. At first I was a bit worried that they were coming from Hong Kong all the way to my home in Minnesota, but after they arrived I had no worries. They came timely and in great shape. I used normal E6000 glue, a toothpick and patience. I glued in one side and waited a bit for it to dry before doing the other side and I think it worked out just fine.