You can replace an old belt on a dryer and install a new belt in about 2 hours with moderate difficulty. You will need the new dryer belt, a bungee cord, a putty knife, a screwdriver and scissors to cut the old belt.
Remove the lid, and examine the belt
Unplug the dryer, and press the putty knife against the clips holding the lid, or top, of the dryer in place. Examine the belt for signs of wear showing replacement is necessary.
Take the front cover off the dryer
Disconnect the electrical cord attached to the dryer's door. Remove the screws holding the front of the dryer in place.
Cut the belt, and pull the dryer drum out
Use the scissors to cut the belt. Pull the drum straight out so you have easy access to the motor and pulley. Lift the front cover up to remove the drum from the dryer.
Position the belt over the drum
Position the belt around the drum with the rubber side touching the drum.
Replace the drum in the dryer
Set the drum back in the dryer, making sure it rests on the rollers. Hold the front of the drum up with the bungee cord. Reach underneath the drum, and position the pulley into the two grooves it sits in. Loop the belt under the pulley. Attach the belt to the drive shaft.
Replace the front of the dryer
Replace the front of the dryer, and reattach the electrical cord to the front door. Replace the top of the dryer and snap it back into place. Plug in the dryer, and it is ready to use.