The Camera system is easy to use for your 3rd person games!
The bottom spline will go under where your player walks to track where the player is, the camera will ten move over the top spline at a matching pace. you can add as many spline points as you want. Each spline point will function as a key point. So when the player reaches the second spline point on the tracking spline, the camera will be on the second spline point on it's spline and so on.
The camera has trouble tracking players going around corners so it's advised that you add a new system in with a trigger box to switch the active cam if you want the player to walk around a corner!