I know this does not help but a friend and I watched the video, then watched the video in the shop and stopped did an operation and then watched the video again for the next step.  After we completed the first receiver we realized that if we would have just taken a few notes watching the video, we would have gotten most of the instructions just looking at a jig.  The guy doing the video has to be a master machinist.  I am sure there are shortcuts but he is trying to make sure everything comes out right.  Taking your time is tough but the finished product is amazing. When you can see the reflections in the walls you just milled out, you know that you have a quality jig.  The most time you will spend is the smallest holes.  The most critical part is the big hole you drill without the jig.  Getting it centered and the jig clamped down are critical.  Don't forget to remove those two screwed in parts before you begin and put them in a baggie in a place you can find them later.