It's going to take big money if you don't know what you're doing.
Find a donor vehicle with the same engine. Same model year doesn't matter TOO much (e.g., 4.0Ls can use 1990-94). You'll need the bracket(s), evap box, control head, PS pump, lines, and gear (and probably Pitman arm), and all the A/C parts. I strongly recommend either buying known-good junkyard parts (find a 609-certified junkyard operator, or they will be junk), or buying ALL-NEW refrigerant parts (around $400).
It's probably cheaper just to buy a truck that has A/C and power steering in it.
Read the sticky at the top of the forum for the A/C. Power steering is much simpler.
