Replacing the belt on this dryer is a complicated process. I recommend contacting a service technician to install this part.
You can view a parts list diagram of your dryer on the Parts link from Sears.com. This will give you a breakdown of the parts in the dryer.
If you feel completely confident that you can safely complete this repair, you can follow these steps to replace the dryer belt:
Replacing the belt on your dryer is a time consuming and difficult task. Be careful if you attempt it because there are many sharp edges you will be exposed to and technicians say it is impossible to do without cutting yourself at least once. These instructions are from the technicians manual. They are:
Disconnect the dryer from the electrical power source.
Remove back panel and plenum.
Remove the motor and blower assembly enough to allow the belt to pass the blower assembly. Two bolts underneath the motor hold it to the base pan of the dryer, removing these bolts will let you slide the motor back enough that you can slide the new belt between the blower and the blower housing.
Lift the drum to slip the belt past the support rollers.
Line the belt up on the wear ring on the tub where the old belt was running. You need to bend the spring on the idler puller so that when the belt is on the motor pulley the spring is pushing the idler pulley against the back of the belt and causing it to be tight.