If you're replacing a belt, use the previously described procedure, but move the accessory toward the engine block after you've loosened the support and adjustment bolts. Then work the belt off the pulleys. Make sure to move the accessory far enough so that the new belt can be installed without forcing it on. If moving the accessory until it is at the inner end of the adjusting slot still does not permit easy installation, you've probably got the wrong belt. Prying a new belt on with a prytool will damage it and could substantially shorten its life.
Where there are two belts and you have to replace the one that is located farther back on the crankshaft, you'll have to remove the front belt first.
Once the belt is over the pulleys, pull the accessory outward and tension it (slotted type adjustment or tension pulley) as described earlier. New belts should be adjusted just a little tighter than ones that are used. It's a good idea to recheck tension after running the engine for five minutes and then again after a few hundred miles of driving.