there's no real step-by-step. look in projects or google "cheromanche"
basically you start by cutting, then you do some filling and body work, then you finish by caging.
cutting up an xj cab is not a good idea if you don't have structural reinforcement in mind...they are unibody and therefore every hole drilled/body panel cut makes it even less strong.
1986 MJ - 3800 camaro powered, 5 speed 4wd
1987 Comanche 4.0 w/ .030 bore, cam, '01 intake, borla header, 62mmTB. auto, full H.O. '99 conversion, 4" lift, d30/d44, 3.55's, 31x10.50 dayton timberline a/t's