There are three ways to adjust the volume on your BMW X3.
Buttons on steering wheel
Press the volume control + or – keys on the multifunction steering wheel to increase or decrease the volume.
Rotary knob on dash
Turn the rotary knob on the power button for entertainment on the center, just below the infotainment system display.
The third way is gesture control by rotating your hand clockwise to increase volume and counterclockwise to decrease volume. Make sure your hand is directly in front of the center screen within the range of the sensor mounted on back view mirror.
These commands will control the volume of the audio that’s currently active, such as when an entertainment source is playing, while having a conversation via Bluetooth connected phone, or while voice guidance is speaking.