I like videos too, but the book version was what I used to rebuild mine and it took me through the steps pretty clearly.
The only stumbling block for us (or at least some EB's) is that while some of the versions of the trans can be disassembled simply by pulling the front bearing cover off and pulling the entire input shaft out from the front, not all can.
Mine had the larger gear and had to come out the top cover in full "top-loader" fashion.
Not a huge problem, but a bit more finicky to finesse back in place.
I originally went down to the library and found the big hardback Chilton's truck book and copied the pages for both the 3-speed and the transfer case. Almost don't need a book for the Dana 20, but it helps to know the specs you're hoping to match, and to verify you're doing something correctly.
Sorry don't have a link to a video, but I'm pretty sure I found one by accident about a year ago or so. Maybe they just don't have good search terms used? Not sure how YouTube sets their stuff up for search.
Good luck.
Paul