Rotate the knob to adjust the volume.Turn on/off the machine.Play the previous music from TF card/USB or your devices.Play the previous radio station under mode.Short press for music play/pause.Long press for radio station automatic searching under mode.TWS connection1.Turn on both karaoke machines and set them to "bt" mode.2.Quickly press twice " " of one of machines. Then you will hear a voice from bothmachine, which means TWS is connected successfully.3.You can connect one of machines to your phone via BT to play the music.Play the next music from TF card/USB or your devices.Play the next radio station under mode.Long press to switch among BT, TF card/USB, LINE IN and .Short press to turn on/off the light and switch the light mode.Charge the machine with the charging cable. When charging, the indicator shows red.After fully charged, the light is off.To add one more wired mic if you need.To connect most devices, like PC, MP3, phone, CD and so on.To play MP3 or WAV music when plugged into a TF card or USB.1.Long press MODE button to "bt".2.Open the BT of your device and search the device "SY-SPEAKER", then click it to pair.3.Only one device can be connected via BT mode once.