Ok press button twice to turn on ay,,yeh if no light on single press it's dead flat and not good for them to discharge so low,,the dji charger wont start them back up if under 2 volt,can check with multimeter,,
Just from your first post,,were you able to power drone up or no breakdancing from the cam,,
Is this drone new or used,,you might by what you've said need to get a new battery just to see if it works ok,,if the drone got no power your app wont conect with it,,bit confused on the motor wont start part if cant get it to power up
Beginner mode wont affect this
Ok dumb question but have you flown drone before ?,dont want to sound rude but you can download a pdf manual which has all you need to know from start to Finnish,or just ask here if stuck,,many can help