If you've welded a tab onto the T-bar to be able to pull them out, than it's pretty simple. It's good practice to set the blades to the midpoint of their ride height adjustment before you start, but no essential.
1)Jack back of car up (can jack on trans).
2)Disconnect anti sway bar.
3) Put rear on jack stands.
4)) Put floor jack under tire, and lift until T-bar is unloaded.
5) Pull T-bar out until threads disengage
6) Move floor jack up or down slightly (depending on which way you want to re-index)
7) Push T bar back in (may have to move tire up and down slightly to get T-bar splines to engage).
8) Put car back down and recheck ride height. Roll the car around a bit so the suspension settles.
9) Repeat if needed until ride height close
12) Do the other side.