Open the CommBox inputs menu from the main home screen.
Select the icon in the bottom right corner.
In the top heading use the small arrows to scroll across to 'sound mode'. Ensure sound output is selected to 'external device'.
Check Sound Bar is powered on using the side soundbar buttons or remote. Press the 'M' button (third from the top) to select the Auxiliary input. You will be able to see a green LED light on the front centre of the soundbar and ensure the volume on the soundbar is turned up.