Removing heater lever controls - 69 280se

Hello! I am starting work on a 69' 280se that is not in too bad shape. I am not very familar with Mercedes automobiles yet, i've only worked on Fords Anyway, the plastic lever controls that control the temp and direction of the air have broken off. Could somebody please tell me what is involved in replacing them? I would imagine the whole dash would have to come apart. If this is the case could somebody guide me on the best way to take the dash apart. I would really appreciate any assistance you could offer.

Adam