David Weaver
I think there's not a great reason for the details. From what I can gather on his youtube video, you start each stone at the highest angle you'll sharpen and work shallower.

If he doesn't talk about squareness or anything, you can figure it out with your own two eyes and hands (i.e, if you're off one way, make a conscious effort to hone more in the other direction).

That's about all there is to it, it works fine. It does work better with stock irons and chisels that aren't too too hard, but I guess so does every other method (unless you can use a grinder on HSS).