It's pretty easy mate, you can't mess your timing up as the timing belt doesn't have to be removed.
From memory, 4 allen headed bolts on the crank pulley for the charger belts, one big nut on the alternator pulley and the same for the charger. Hardest part is holding them still whilst undoing the nuts on the alt' and charger. You can use a rubber chain whip thingy or similar to help. Once off, swap the pulleys for the new ones, the crank pulley bolts are slightly offset to stop you putting it on the wrong way (so the timing marks stay the same). Tighten it all up (torques in Haynes for crank pulley) and put the belt on, presumably you know how to tension the charger? If not there's a FAQ for removal and refitting that will cover it.
You may find that you need to drop the left hand side of the engine down to get access to the bolts on the crank pulley, I think I've done this before by raising the gear box end to get the angle, but I can't be sure from memory.
One thing that might catch you out is don't try to undo the big bolt on the crank pulley. It's not actually holding the auxiliary pulley on. It looks like it is, but it's actually holding the main timing pulley on and you don't really want that to come off...