Changing the driveshaft boot
With the roadwheel still in place, remove the wheel nut securing pin and the crown, then loosen the wheel nut (the one on the CV joint) about a quarter of a turn or so, just enough to get it going. Applying the park brake or even the foot brake (assuming the system is still under pressure) will help. Loosen the wheel bolts slightly, then release the park brake.
Depressurise the suspension (put into bottom position while ignition is still one). Take off the wheel, remove the nuts on the bottom ball joint and the steering ball joint, pop out the joints (normally you need a special tool for at least the steering joint, but sometimes you can help yourself with a tap or two of a copper or brass hammer--do not use a steel hammer!!!).
Take off the wheel nut on the CV joint completely. You had to loosen this before because the wheel holds the brake disks , and once you remove the wheel, the disk is only held by a small hex screw which easily bends or breaks off if you try to loosen the nut when the wheel is off and the brakes are on. The CV joint should be free at this point. The front suspension rod is movable enough so you can remove the CV joint from the wheel hub, usually by twisting it a bit outwards and either to the left or the right, like turning the wheel at right angles to the straight ahead direction. At this point you have to be quite careful not to disconnect the driveshaft from the cross joint or gearbox, so don't pull on it excessively.
Get the old boot off, by cutting the ring clamps (the new boot should come with new ring clamps), and getting rid of all the parts. Keep the plastic rings on the boot itself, they might come in handy.
Take the CV joint off the driveshaft. This needs a little trick and a third hand. Hold the shaft and have someone hold the joint, then use the already mentioned copper or brass hammer and tap the outer rim of the joint, outwards (on a RHS wheel, it has to go further to the right). The driveshaft has a sprung ring at the end that keeps it inside the CV joint. Don't even try pulling the joint off, you won't succeed if the ring is intact, you really have to give it a lot of force in a short time to get the spring to contract and the shaft to go out, hence the need for the hammer. You can keep the driveshaft itself immobile by just holding onto it tight.
Once you have the joint removed, insure that the shaft doesn't get pulled out of the gearbox by gravity: tie it to the surrounding parts with a some string or wire.
If you find dirt, even only traces thereof, in the grease inside, you should consider disassembling the CV joint and disassembling it. The problem is that it is rather difficult to describe this reliably and be sure that someone attempting this will be able to put the whole thing back together again... The trick is to turn the inner crown upside down; since there are six balls in the CV joint, there are six ways this can be done at first glance, however, only one way will actually work. This is because one of the grooves for the balls is made longer deliberately--after all someone had to assemble the thing in the first place!
Basically, you keep turning the inner crown over each time removing two balls, starting with the direction that removes the pair in which one ball is in the longer groove. Unless all the grease is removed first, it will be difficult or even impossible to see which groove that is. Assembly is by the exactly opposite procedure but putting in the last pair of balls back is tricky: you have to put one inside the CV joint cavity and let it be inserted into the groove and crown as you turn the crown into its final position. If you have an old CV joint somehwere, it's worth playing with it until you can figure it out.
Clean the dirt from the driveshaft a couple of inches beyond where the old boot reached, then put the new thin white plastic ring you received with the boot, together with the smaller clamp, onto the driveshaft.
The boot comes with two or three plastic rings, that go into the grooves in the boot and are designed to prevent folding of the rubber and, consequently, to avoid ripping of the boot. Be sure to have them on the boot in their proper grooves. If you don't, the boot will not last very long. Put the boot onto the driveshaft and get the driveshaft side over the white plastic ring. Use the new grease that comes in the kit to fill up the CV joint. The best way to do this is really with a dissasembled joint, but failing that what you do is push the grease inside through the hole where the driveshaft goes. A lot of grease should go in until you can see it coming out between the steel balls. Usually almost all of the grease supplied will go into the joint. You can spread the rest out over the balls, but don't contaminate the outer rim where the boot goes, if you do, wipe it off. It's a dirty job, but that's the proper way to do it.
Put the joint back on the driveshaft, this time you will need to tap it with the hammer on the shaft on the joint to get the driveshaft in. This will also press quite a lot of grease out through the openings around the steel balls, but this is perfectly fine. Now pull the boot onto the joint, taking care that the rubber is not strained and has no folds, then fasten the outer clamp. The clamp is usually tightened by a special tool but you can use nail pulling pliers or a similar tool with some care.
Hold the CV joint coaxially with the driveshaft, and check that the other end of the boot (with the white plastic ring) is properly seated in the groove in the shaft. When you are sure, tighten the smaller clamp. Put the CV joint back into the wheel hub, the operation is similar to taking it off, be careful not to pull the driveshaft out of the cross joint or the gearbox, tighten the wheel nut the best you can at this point, just enough to hold the joint in without wiggle, you won't be able to do much without the wheel on.
Check the conical seats on the bottom ball joint and the steering ball joint, wipe it off with a cloth, as well as the conical holes where they get fitted. There must be no dirt or grease in these. Put the bottom ball joint back into its seat and tighten the nut somewhat, then do the same with the steering ball joint (a light tap on top of it can help get it into place properly).
Tighten the ball joints. If they turn inside the ball, notice there is a hex wrench hole in the joint's conical shaft to apply counter torque until the cone starts holding.
Check that everything and if OK put the wheel back on. You will not be able to tighten the wheel properly unless you are doing so with a compressed air driver, but you should be able to do enough for the next step. Get the engine going and the pressure on, to be able to apply good braking power. Put the park brake on, or even better have someone press on the foot brake. Tighten the central nut on the CV joint, replace the nut securing crown and pin. Tighten the wheel bolts properly if needed.