I purchased a P3S used off of local CL. Bird had not been flown for a long time. Had not been registered,etc. when I went to pick up the owner showed me on his iPhone how to turn on and how to use the controller. The motors would not start and there was a notice on his device that in part stated that the IMU had to be calibrated. I figured I could do that when I got home. At home I put the DJIGo app on my iPhone 6+, the P3 would not connect. I called the previous owner and he could not rember the password he used when he first set up the drone. As you can tell I am a experienced drone pilot and at 79 may be way over my head. An old man with a young spirit wanting to have a good time with my Grandson. Help please!!!