Standard Held belt designs feature a single or dual snap set that allows for the free exchange of buckles.
Once you have removed the buckle and you are reinserting it, it can be a little confusing. This video offers pointers within the demonstration to help avoid mistakes.
For example, the ring keeper must go in first, this piece holds the strap down after it is notched.
A center bar buckle extends in a full circle and self-contains the strap, eliminating the need for a keeper ring.
Not all buckle types are interchangeable. Especially flat panel buckles require a different type of design with smaller notches.
Look for additional buckles available in the shop as an add-on at checkout.