Spanner juggler has almost said it all in terms of fitting. I would say though it is much easier if you remove the caliper and disc/hub assembly. Be sure to hang the caliper with a cable tie so there is no strain on the brake pipe and do not over-tighten the wheel bearing when re-fitting the hub (which is also an opportunity to massage a little more HMP grease into the wheel bearings. the rear 5/16th" nut and bolt on the lower plate is also the anchor for the rear tie rod to the chassis. You will need to loosen the three bolts which connect this to the chassis in order to move the tie rod out of the way (as in my first picture). Hope this helps.
The reason he didn't is as you describe above ;-). It can be done without the hub removal and many owners (I don't get weekly emails but it's close ;-)) struggle to get the hub nut split pin out and then again are unsure on the end float setting procedure to refit it. Of course it's easier with the hub and disc out of the way however it does bring in a range of skills and knowledge that may well be a stretch for some.
