after taking off the rear door panel, you have to drill a couple of holes for the threaded inserts. Then bolt the square tubes to the door using bolts into the threaded inserts, then drop the guard into the tubes to check fit. take guard back off, mark the door panel and drill out, then re-fit the door panel, then re-fit the dog guard. finally, do up the two fasteners to hold the guard in place.
you should have a piece of plastic wrapped card with all the fixtures and fittings shrunk wrapped under the plastic.
If you do a search on the RAVE CD (greenoval.com), you should find the full instructions. Dog Guard is Part No. STC 53047
BE WARNED, the templates don't line up fantastically, and it will need a bit of fettling.
If you can't get the instructions, pm me and I'll send you a copy, as I'm anal enough to have kept the instructions when I fitted mine.