Disconnect power supply.
Turn mower upside down and remove blade.
Remove the five screws holding motor to lawnmower chassis.
Turn lawnmower back over and remove four screws holding top cover.
Lift cover off to expose motor.
Lift motor from lawnmower chassis to get to belt
Remove old damaged belt. Check both belt drive wheels for any wear and clean.
Replace with new belt, This will be a tight fit.
Soak new belt in hot water to allow some flexing.
Place new belt onto notched drive wheel first then guide it over the larger flanged wheel as far as you can, turn wheel to ease the belt onto the wheel.
Check that it turns smoothly making sure the belt sits into notches. Replace motor into lawnmower chassis. Turn lawnmower on side and replace the five holding screws.
Replace top cover, Replace blade.
Connect to power supply and test.
Rick, March 2016