See attached link. The first thing you need to do is take the deck off. Once you have the deck off you will see a double pulley on the bottom of the engine. There will be a couple of studs(belt guides) that stick down to keep the belt from coming off of the pulley. Take those out. Take a look at the rest of the belt on how it is routed before you take it off. Once you have looked at it push the clutch pedal in and set the parking brake. This will put slack in the belt. Take the belt off of all of the pulleys and then put it back on as shown in the picture and then put it all back together.