How do you use those index blocks ?

I got a new 8inch ballistic advantage 8inch flutted threaded barrel for $140. Shipped. Got a used 1022 wood rifle stock oem and used oem barrel. New charging handle and bolt and stock takedown screw for $135 Shipped Also have new hogue overmold stock for 64 shipped

I got a oem omplete g17 build kit minus the stripped frame for $330 shipped.

https://imgur.com/a/UxRnnAf