Start on his Legacy Projects page where you'll find articles on the original Zen, Zen Revisited, Son of Zen, etc.

http://www.passdiy.com/legacy.htm

His amps page has articles on Zen Variations Parts 1 to 6.

http://www.passdiy.com/amps.htm

Not sure what your building experience is like. But if you've already built a couple of kits with point-to-point wiring, these projects should be pretty simple. I usually find the hardest part is chassis prep.

Gar.