Jack the cap, support it properly, remove drivers side wheel for easier access, place drivers wheel under car in case your support goes.
Looking from under the car located at the front of the engine at the PS pump, where the PS belt goes over, you'll see some bolts holding the PS pump in place, iirc (done it over 6months ago and only once ever) there are 2 or 3 bolts that I loosened (might only be 1), which will allow you to tighten / slack off the belt by rocking the pump up/down.
I did mine pretty much at the spur of the moment without any research, it took me about 4 hours but that was only because I had my father in law telling me not to loosen the bolts because it looked important
He buggered off inside to make a cuppa and I loosened the bolts, whipped the PS belt over and by the time he came back out I was getting the alternator belt tensioned properly
It will make sense once you have your head under the car.
