The camera and gimbal always get hot when powered on and not flying, so don't panic about that. Go into the DJI go app and tap the controller icon at the top then select link RC, once you've tapped that you'll have a 1 minute countdown to locate the button on the drone and press and hold it for 2 seconds which will sync them together. The button is located next to the landing gear strut at the rear right hand side, it's deep set but should be flashing red whilst the pairing is happening.
Hope that helps and good luck.