Your computer will transmit audio via the video connections, such as HDMI cables.
If audio is not working, please go to your sound settings and choose the correct output device. This is typically listed as the monitor that is connected to the KVM because the audio is transmitting via the video connections.
If you have an external device plugged into the audio mini-jack, the switch duplicates the audio signal from the HDMI input to the monitor and mini-jack out.
Generally we just try all of the outputs one of them is correct.