The 910XT does not have Bluetooth capabilities so you cannot sync using the Garmin Connect Mobile app on your phone. You have to use the USB ANT stick that came with your watch and a computer with Garmin Express installed.
Once you've synced using Garmin Express, you can view the data on your phone using the Garmin Connect app or by going to the web site Garmin Connect [https://connect.garmin.com/modern/]
