Turn over the Bluetooth printer or scanner and make it discoverable. The way in which to make the Bluetooth printer or scanner discoverable relies on the device. To learn the way to make the Bluetooth printer or scanner discoverable, check the device's documentation or take a look at the https://www.bluetoothspeaker.top/tws-support-tf-card-playing-waterproof-music-player-bluetooth-speaker-best-sound/