You need to scan the QR code in the manual to download the application, or search and download "YFIT" in the application market
Or visit: http://www.decadesmart.com/yfit/download.html
Turn on the Bluetooth of the mobile phone, select [Add watch] in the APP, and select "SN88" to connect
Once the connection is successful, the date, time and language on the watch will be automatically updated