Set up your audio device
1. Click the Options icon (Shown here on the far right as a Gear Wheel.)
This will open the Skype for Business - Options menu.
2. From the Skype for Business - Options menu, select the Audio Device Option.
3. Pick your device from the Audio Device menu, and adjust the speaker and mic volume.
4. You can click the Check Call Quality to run a test of both Microphone and speaker of your device.