I made an AMD-65 a long time ago. I used an 80% receiver where I had to drill the holes and install the lower rails. Now you can get one with the rails already installed.
80% AK47 Receiver Blank - Henderson Defense Industries
I took it apart and built it again with a tapco flat. Just to see if I could do it. The best way to bend a flat is to get a press and a jig. I made a jig out of a block of wood and bent it with a hammer and another block of wood.
Both times I drilled and tapped, then screwed the receiver to the trunions. I also screwed the lower rails into place. Rivits would have looked better as well as spot welding the lower rails into place. I heat treated the rails and holes with a MAPP torch. It was ugly, But it worked. I took it apart and sold the pieces to somebody that did a better job.
Best way is to go to a build party. Where people have all the tools. BTW: There is a response video showing where the guy in the original video committed 3 felonies during his build and disposal.
Here is the response video