The adapter is literally a "Snap it in" procedure. Just as if it was a Saiga Magazine. There will be instructions. There's 2 things that basically need to be done. A very small amount of dremel on the back side of the Saiga mag release paddle lever that you push to release the magazine. It doesn't quite seat far enough, so a slight touch with the dremel will let it go further to hold the adapter in place.
The other part, which is definitely a little bit of work with the dremel, is to grind the 2 tabs that are part of the trunnion. If you try right now to put in an AR15 magazine, you'll see that it can really go up all the way. These two tabs stop it. So, you'll need to grind it so the AR magazine can go in deeper. Wait until you get the adapter, so you'll know how much to grind. Once the magazine can go all the way up through the adapter, and CLICK into play like an AR magazine should, you'll be far enough. Hard to judge without the adapter on hand. I did some of the grinding ahead of time. I didn't screw the pooch, but I really wish I had waited. Then I could have done a nicer job.
But Renegadebuck includes really good instruction. later.. mike...