When you power on your R/C (remote/controller) with your device plugged into the mini usb, the 1st time it should ask which app you would like to associate the R/C with. At this point you should also be able to select whether you want it to access the app just this time only, or always. It's best that you select this to always use the app you are currently using it with for the upcoming flight. Unfortunately the main reason for this is should your device overheat and cause a complete shut down, as long as you have the setting to always connect to the app with the device being used, it will automatically start back back up in the event of a shut down. The main purpose for this thread is to inform you to calibrate the compass prior to each flight. Other then laziness, there is no excuse to not calibrate before each flight. DJI has built a audible message to complete the aircraft status prior to flying. When you click to enter camera view, you are directed to the Aircraft Status section. And right there is plain sight is the option to begin the Compass Calibration process. If it's not there then it should read normal, or be ok. Otherwise when completing the process you must have flashing green lights, if not then it is a failed calibration and you will need to run the process once again. The system will not pass a failed process.