Here is a quick overview of your TCL Alto 9+ Sound Bar

Main Sound Bar unit

1. You can press the Power  button to turn the Sound Bar main unit on or off
2. Press the input  button to switch the audio source among AUX/Bluetooth/Optical/HDMI in/HDMI ARC/USB modes
3. Press  to select the Bluetooth source. Press and hold to enter pairing mode.
4. Press the - to decrease the volume level.
5. Press the + o increase the volume level.
6. Front LED display: Indicates the Sound Bar status (e.g. volume level, sound bar status).
7. Green/red LED:  Indicates Wi-Fi connection (e.g. Green: connected. Red: disconnected).   
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8. AC input power connector
9. USB Type A connector (only for music playback)
10. Optical input connector
11. AUX input connector
12. HDMI OUT (ARC) connector
13. HDMI IN connector

Wireless Subwoofer

1. Power port: Connect included power cord. 
2. LED indicator
   • Slowly flashes when the subwoofer is in standby mode
   • Slowly flashes when the subwoofer is in standby mode
   • Solid light when successfully paired with the sound bar
3. PAIR: Press to activate pairing with the Sound Bar main unit.

Note: The subwoofer is already paired with the subwoofer out-of-the-box. Manual pairing is needed only in case of troubleshooting.