I'll try to be quick...
So I'm wanting to replace the two climate control fan buttons. [emoji3484]
Easy? No way!
The total unit must be removed from the car's dash.
Facia must be separated from control unit using T6 hex bit (tiny).
Heres the trick...
Once the two are separated...(facia and control unit.)
The buttons are pushed/sled backwards [emoji3591] be removed, and then replacement buttons are sled in from the back(loaded) to the front[emoji3594]. Then attach together by screwing in the tiny 6 to 7 screws.

One would think the buttons can be pryed up from the front using a small flathead...oh no!
Too simple.
It's a BMW...[emoji106]


Replacement buttons



Worn buttons