I tried to google for this and watched some youtube videos but I'm a bit frustrated because they all seem to be out of focus, don't zoom in enough for me to see which part fits which other part, etc. I found a video by Tandy that might be good except that it's all low-contrast brown leather on brown work surface. I just can't see enough detail to be able to know which of the four snap pieces goes with the other piece.

I've also been fiddling a bit and can't figure it out on my own. I use rivets a lot and know how to set line 20 snaps - and I know those are different, but I just add it to say that I do have some of the basic skills.

Can someone point me to a decent tutorial?

Edited to add a picture of what I have.

The cap is pretty obvious, but I can't tell which of the other three is supposed to fit into the cap. If I can figure that out, then maybe I can figure out the rest. I'm using snap setters for line 16 snaps.