It's really easy, it took me about 30 minutes, a lot of that was hunting for the right sized/style of tools in the shed.
4 nuts to undo - there's 2 17mm one atop each mount that attaches them to the brackets mounted to the t-case, the smaller mount (driver side) is a bit awkward but if you have a 17mm ratchet spanner with a swivel head it's super simple. 15mm nuts underneath on both. Or at least this is what mine had.
I used an impact gun on the 15's.
Once all undone and nuts removed, jack up the the transfer case as high as it will go, you can then wiggle the old mounts out and the new mounts in. Drop the tcase back down slowly to make sure the locating pins on the new mounts line up with the brackets, then refit and do up all the nuts.