Hate those none insured you know who types
They come off completely, the two bolts u need to remove are covered with rubber cover. I had to use a Hex 45 I think, as a 6 or 8mm allan key wouldnt do the job, knowing the awkwardness of car companies it could be a 7mm key. Once its off make sure the piston is back, place in the new pads and put back on over the discs and replace bolts.
Also get the right pads for the car, I know from experience as some eijit from Hi-Q fitted the wrong discs with the right pads on the car when my mother owned it . There are different types available, ie the size of the discs/pads. A hint: There is a 3 letter code on the sticker for the car in the service manual. One code corresponds to the brakes.