if it takes you more than an hour to do all 3 calipers i would be surprised. basically it's the same for all 3, unscrew the slotted cap (can be a pain to undo) on the caliper underneath you will then see an allen head bolt, unscrew that pull out pads use the old ones to push the pistons on the caliper back in, slide in new pads making sure they are located right in at the top, put allen head bolt in and the cap screw, job done.
Iain