Article: This can usually be found posted underneath the hood of your car or in your service manual for serpentine belts (S-belts). If you drive a much older car, you may have a multi-belt design (V-belt). Either way, if you cannot find a routing diagram you should take a picture or draw one before removing the belt(s). Be sure to make note of whether the grooved side or flat side of the belt makes contact with each pulley. It is important not to put the new belt on backwards. There are a few things to remember when releasing tension on a belt.  For serpentine belts this is done by compressing the spring loaded tensioner. The tensioner is just another pulley that the belt runs over, but only serves to keep tension on the belt and does not power any accessories. Some tensioners can be compressed by turning them with simple hand tools such as a wrench, and others may require a special tool. Usually twisting the pulley clockwise will compress the spring. V-belts do not have an automatic tensioner. They can be removed by adjusting the position of one of their pulleys to release tension. To loosen a pulley, turn it with a wrench or specialized tool. By convention, counter-clockwise will loosen the pulley. Once tension is released, the belt should slide off of the other pulleys easily. One reason for a damaged belt is a malfunctioning pulley. You should check the tensioner and all pulleys that the belt contacts. If one wobbles or does not spin freely then you may need to replace it.

What is a summary?
Locate a routing diagram. Release the tension on the belt. Remove the belt. Check the pulleys.