Remove the heater cover from the wall by using a reciprocating saw and cutting the screws that secure the heater to the wall. Some heater models might only require simply unscrewing the covers from the units.
Pry the adjustable damper loose and remove it from the hangers.
Pop the hangers out by using a screwdriver to pry them from the back plate.
Remove the back plate from behind the heating element.
Secure the hangers of the new heater cover to the unit.
Screw the back plate to the wall studs.