Need help on belt replacment!!!

[BoomInTheTrunk]

I have a 1981 300d and I need to replace the alternator, water pump belt. I have already just cut the old belt off because I put in the larger AL129x alternator because of the stereo that i have, and needed to take it back out which lead to me cutting the belt because it was so tight. All I need to know is how to loosen the belt on the power steering pump. and how to re-tighten it after putting it back together. I have seen it done before but it was about 2 years ago and forgot. I went ahead and bought a larger belt 41.5 inches hopefully this will do the trick. Pictures would be greatly appreciated.