How to use the new Unity ads?

I updated to Unity 5.2 and it said that you no longer need to use SDK to use the unity ads. I turned on Unity ads in the services section in the editor, created an account and everything (I think) to get going with unity ads. As a test I created a script that makes the add pop up every ten seconds.

  void Start()
     {
         Advertisement.Initialize ("<YOUR GAME ID HERE>");
     }
 
     void Update()
     {
         timer -= Time.deltaTime;
         ShowAd ();
     }
 
     public void ShowAd()
     {
         if (Advertisement.IsReady () && timer <= 0) 
         {
             Advertisement.Show ();
             timer = 10.0f;
         }
     }

it appears to work as when I'm in play mode every ten seconds this comes up:

Is there anything else I need to really get unity ads to start working, how do I get rid of the "here would be your ad unit" picture, so that a picture for a real game was to show up, and If I was to build and release my game right now would I make money off of the ads or do I need something else?

thanks for the answers in advance.