Have a search on Google for mk4 golf handbrake cable change, think it's pretty much the same process as that. Something along the lines of jack rear of car up, support on axle stands, release handbrake, loosen cables under rear ash tray, release cable once loosened, go back under the car and release cable from caliper, pull cables through and repeat process back to front for fitting new ones. But would check with the golf mk4 as not too sure, I also need to do my cables soon so will be following the same process