I will try one more time. The monitor in your coach has three camera inputs. One for backup, one for driver side, and one for passenger side. There are also three trigger lines, one for each camera.
The default camera is the backup camera. When you turn the system on that is the view you will get. Also when the coach is in reverse the backup camera trigger over rides the other triggers.
The front directional lights are excellent trigger points for your driver and passenger camera control. Even though the light is flashing the monitor is designed to ignore the flashing and keep the specified camera on until the directional is turned off. The system then goes back to the default rear camera.
The only exception to this is if you are backing up and have your directional on the side camera will not activate as the rear camera has priority over the side cameras.
Manual for your system can be found here. It looks like a real nice system. Should work well. I would go on eBay and get a cheep DVR to add to it to record what happens around you. Good insurance.