Insert the Bluetooth module into the Nyboard downloader socket and open the serial downloader to search for the Bluetooth signal of Bittle-xxxx (random number). The default password for pairing is “1234” or “0000” (for the convenience of connection, the default password for the newer version is set to “0000”). Please enter the password before pairing. After the pairing is successful, the system will assign a serial port number, and you can select the corresponding serial port number on the Arduino.