RepairClinic.com, Appliance-Repair-It.com, Repair2000.com and ApplianceRepair.net all have diagrams on fixing, or replacing, dryer belts. All of the sites have installation tips, tutorials or step-by-step guides on belt repair procedures.
Disconnect the power by unplugging, or tripping the breaker to, the electricity. Access the belt by removing the top and front panels of the dryer that are attached with screws. On some models, the lint trap may need to be separated also. Remove the old belt by pushing the tensioner pulley to the right to release the belt pressure. Install the new belt with the same method, making sure the grooves are correctly orientated.