After the Bluetooth board, refer to the wiring diagram below to solder the speaker and 3.7V lithium battery, and then check that the battery is not connected reversely. You can turn on the power test. Turn on the switch and the blue indicator light should light up. If it does not light up, you should quickly turn off the power to check whether the battery is installed correctly. When the indicator light is on and there is a ding- prompt sound, you can turn on the mobile phone Bluetooth to refresh the Bluetooth name, find "DAU Audio" to connect and play the music on the mobile phone. Regarding pairing, if you buy two DAU Audio Bluetooth modules, they can be paired in stereo. You need to turn off the Bluetooth of your mobile phone first, then turn on both boards at the same time, wait for a few seconds to hear the prompt tone, then the blue indicator light of one module is always on, and the indicator light of the other module is still flashing, indicating that the pairing is successful. Then turn on the mobile phone to connect Bluetooth, and you have a stereo wireless speaker. It is recommended to use a 500mAh-2000mAh capacity 3.7V lithium battery, and a 5V 1A-2A charger, and use a USB2.0 to Type-C cable for charging. Working voltage: DC3.5V-5V Speaker: 2-4 (3W-10W), can connect one 2 speaker or two 4 speakers at the same time Charger: 5V/1A is recommended Charging interface: Type-c Headphone jack: 3.5mm Battery: 3.7V polymer lithium battery or 18650 lithium battery (customers need to prepare their own batteries) Size: 28.5mm x 17.3mm It's DIY kits, needs to finish by yourself. (Different batches may have different printed words, which not affect the use) Color: Material: ABS Package Contents: 5 * Mono amplifier decoding board (There are different batches, and the printed words are different) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.