New to the forum! Help with making a strop?

I've ventured into DE shaving, but I much prefer straight shaving now. In the process of making a strop. I have 3" wide 21" long leather from Tandys, and I was wondering what kind of cloth would I need to use for the backside of the strop? And where can I purchase those metal rings for the strop?

I got the metal rings and Chicago screws at Tandy.

Barring that I would try a tack Shop or Sailing shop that carries rigging supplies

All the Tandy Leather shops should have the screws/rivets and rings for you. If you're looking to make one on the cheap, you could just punch a hole in the top center and slide it over a hook. Linen or cotton webbing are typically used for the fabric component; you may just have to google that one though.