Unplug the machine.
Remove the lid ( 2 screws towards the front sides).
Obtain the CORRECT new belt, from Miele.
Lean over the machine from the front, put hands down behind the drum, loop the belt over the motor pulley near the bottom of the machine, keep the tension & get as much of the belt over the pulley wheel as possible. Then with both hands on the big pulley wheel, turn the wheel without letting the belt slip off.
Check to make sure the belt is central on the motor pulley. If not, adjust.
The belt will be very tight. Use gloves. There are some very sharp edges.
If the belt has broken or shredded, then almost certainly the dampers of the machine are worn, causing the drum to bounce around too much.
Bernii, November 2010