See also:

Adjusting volume
Turn knob 1next to the CD/DVD player until the desired volume is obtained. You can also adjust the volume with buttons on the steering wheel. ...

Controller
Select menu items and create settings. 1. Turn. 2. Press. 3. Move in four directions. Buttons on controller ...

Selecting a channel
You can only listen to enabled channels. The selected channel is stored for the remote control currently in use. Via iDrive1.  "Radio" 2.  "Satellite radio" 3.  ...