To connect your TomTom Multi-Sport Watch to the OnePlus 3, first you need to go to Google play store to download and install the TomTom My Sports app.
Once you have installed and opened the App, you will need to create and use an existing TomTom Multi-Sport Watch account for the phone.
Before pressing Tap to Connect, you need to make sure you go to the TomTom Multi-Sport Watch's Settings -> Phone -> Pair New. The TomTom watch will then become visible to the App. Of course, make sure the phone's Bluetooth is enabled.
After you select the TomTom Multi-Sport Watch, you need to enter the PIN that you see on the watch. You'll then need to enter the PIN displayed on the watch into the App to establish pairing between the phone and watch.
Once pairing is successful, your watch will show as 'Connected' with the OnePlus 3. If there is any tracking data stored on the watch, it will get automatically downloaded to the App and then upload to TomTom's cloud server.
Once the watch is connected to your phone, you can track your location, speed, and other activities supported by the watch.
The connection setup between the TomTom Multi-Sport Watch to the OnePlus 3 took only a few minutes without any inconvenience. The TomTom Multi-Sport Watch works well and is able to sync its data with the OnePlus 3 over Bluetooth.