support the truck by the frame using jackstands high enough so you have have the rear suspension at full droop and then some, un u-bolt both sides, let the axle drop using your jack, put blocks in, u-bolt back together. not much to it.
i just used regular jackstands when i did mine. the rear-end was almost sitting on the ground. but it worked out. getting the tires back isn't a problem. all you need is enough room to get the floor jack under the diff when you're done and you can jack it up as far as you need to get the tires back on. I've never done it before and it took me about a total of 2 hrs to install the blocks and shocks, and that was with about 20 minutes of goingonline to make sure they sent me the right shocks. (they seemed a bit short)