On a gti?
Mine was simple.... if I remember correctly you remove the plastic cover on the handbreak, you can see where the cable attaches, can't remeber what tools you need

but if you have a set of screwdrivers, and a socket set there shouldn't be any troubles! diconnect inside the car, then with the car
securely jacked up, unclip the other end from the caliper then pull the cable out(or the other way around! sorry

). Then fitting is reverse of removal! I'd do both at the same time.
terrible explaination but it wasn't overly difficult.
good luck