My serpentine belt is cracked in multiple places and it's time for me to replace it. I have never done this before, though, so how do I do it? I know I have to release tension on the belt first via the belt tensioner, but how exactly is this done? I thought I would take a couple of digital pictures of the original belt route so that I can duplicate it while putting the new belt on. Any other advice? What tools do I need?