fairly easy job, did mine in a mall parking lot.... I installed new oil pump while mine was apart, bein the type of mechanic I am I did prime the oil pump.. all timing marks are on the the inner belt cover.... I used jack handle to release TB tensioner and locked it down with the travel guide bolt, (you can also use oem bottle jack resting on L frame rail to push TB tensioner into position and lock it down for re-assembly) I recommend replacing TB tensioner while you have it apart, if not, be sure to clean tensioner so it moves freely with belt wear.. .
NOTE: you will need harmonic balancer puller.....
you will have to remove A/C compressor, some say you can fanaggle it out of the way without removing the lines (I tried and cldnt).....
remove radiator a must (good reason to flush n winterize)
you will have to lay breaker bar onto L frame rail to break loose harmonic balancer bolt (be careful)
I removed TB cover assembly to watch for ware, and I can get to everything with out dis assembling (your preference) my truck never sees mud
just a pic to show bolt to lock tensioner in place with installing new belt, pay no att' to cam mark as seen below