Easy job to do. Just make sure you disconnect your battery before you start.
Remove cables from the back of the starter, easiest to get to from under the car.
Remove two bolts, I can't remember if the bolt from the gearbox side into the starter or from the starter side into the gearbox. Either way undo these two bolts, they can be a bit tricky. Then bolt the new starter in place, attach wires, reconnect the battery and away you go.