Rivet / Eyelet machine

Has anyone managed to use the big green rivet machine successfully?

I’ve watched a few YouTube videos and I can’t work out if I’m an idiot (very possible) or a part is missing from the machine we have.

I used it just before Christmas - which fabric are you trying to rivet? I had some difficulty with one section where there were 4 layers, but it worked reasonably well on 2 layers

I didn’t get beyond ‘try a test rivet in some scrap fabric.’