I have the exact same model and thought at first that this was a problem too. Your right the user manual is next to useless. I have discovered that all the cameras set up are in fact recording, it is just that you can only view two of them at the same time. If you go to the bottom of the screen when you are in playback mode you can deselect one of the cameras and re-select another one. This way you can view all the camera footage although not at the same time.