Use the camera layer to position and aim the camera the same way you use your photo camera. Since there's only a single render window there can be only a single camera layer. The first layer is always the camera layer and you can't delete the camera layer.
The position of the camera. Note that moving the camera to the left has the same effect as moving the scene to the right. Moving the camera can be handy if you want to move all layers at the same time.
This is the direction towards the camera is pointing.
The Field of View (FOV) determines how much you can see of the scene. A small FOV reduces the perspective 3D effect, a big FOV looks like a fish eye lense.
This is the distance between the camera position and the camera rotation centre. When this property is not zero, the camera position is the rotation centre around which the actual camera rotates. You can create spectacular movie like camera movements with this effect.