videos on youtube, booklets on amazon and ebay and midway usually has them too.
But easy to start, once the butt pad is off, you need a long flat head screwdriver and remove one screw. the back pops off and all but the rotary mag is exposed. Unscrew the fore grip to access the mag. That real long screwdriver or a ratchet with long extension seems to be the only tool that really causes the project to take longer than necessary.