Can I use Bluetooth headphones?
Before enabling the Booster, make sure your Bluetooth headphones are connected to your device. When your headphones are connected, you'll see an indicator in the status bar at the top of the screen, as shown in the following screenshot:

Note that "connected" is different from "paired." "Paired" means your device has been programmed to recognize a Bluetooth device, and "connected" means there is an active connection to that device.