The quick tip by Drone Shop Canada is a time saver for your DJI drone. 

Turn on the Phantom or Inspire or similar remote controller while it is connected to your phone or tablet. 

Click the C1 button on the back of the controller and it will signal your device to launch the DJI GO app


Simple as that, and its a good test to make sure the usb cable is good and your device is connecting with the remote controller.