The zone selector buttons allow you to choose which zone of your system you wish to adjust. There's plenty of space for a label to make sure you know exactly which part of the system you are controlling.
Once you have selected your zone, you can then choose a music source to be routed to that zone.
The music level control will then allow you to adjust the level of your chosen source, in your chosen zone.
A full guide to system status indicators can be found here - Zone - LED Status
In addition, the two microphone inputs have individual level controls to enable your message to be heard at just the right volume in each zone. Select the zone and adjust the relevant mic level control.
Should you wish to control the microphone levels in all zones at once, hit the button above the known for either Mic 1 or 2. The final control for allows volume control for the paging stations.
Finally, there is a removable fan filter cover. It is recommended that this is cleaned after significant dust build up.