You just need to start your unit with click the blue button twice to start it. And twice to end it. Then sync the session with the app.

better to initiates the session with the phone app , once it is going you can turn the phone app off as the battery of the device and your phone are taxed by the continuous sync. so if I use the iPhone on while I do an activity it u I get approx 24 hours from the X2, if I initiate it from the app the close the app on iPhone I get considerably more than 24 hours from the X2. initiating it from the phone allows you to choose the activity type. but you can also do that later post activity. When you’re finishing your activity open the app again it will automatically syn and you can then turn it off and initiate sync of data. but you can amke sure it is on properly on teh phoen first adn tehn close the app teh session keeps going.