This job is pretty easy, even for the none technical owner. Check out the link Paul has put up and make sure you have a full set of clips number 6 & 7, as these are the single use clips you will hear breaking as you pull the skirts off. I also used new expanding rivets (number 9) throughout when putting the new skirts on. The old ones get clogged up with muck so you will destroy a few as you take them off, think about 50% got ruined as they had been on my car 3 yrs before taking them off. Before undoing the expanding rivets give them a good soaking of WD40 (a few times) and let it soak in properly. Others may have something better for releasing the rivets.
Oh and be very careful taking your sill strips off as they tend to crease if you're not. Be a good excuse to get some
JCW ones though, about £35.