USB tethering is a way to share your phone's connection to your PC. Activating it will allow AudioRelay to send audio directly through a USB cable.
Connect your Android device to your PC via a USB cable
Enable USB tethering in your phone's settings
Your PC will take a few moments to configure the connection
Go back to AudioRelay, you can now click on the new server entry!
Sharing your connection means that your PC could use your mobile data. Depending on your mobile plan, it could cause additional charges.
You can prevent this risk by doing one these steps on your phone:
Connect to a Wifi network
Disable mobile data
Switch on airplane mode