How do you change a serpentine water pump belt on a1996 Cadillac sedan deville?

Same exact thing happened to my '96 cadillac deville just last week. The belt actually shredded. If you look at the location of the belt (right at the lower right corner of the engine) you may decide you may not want to mess with it yourself. I didn't. I took it in to Firestone and they fixed it parts/labor for $60