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.

At https://unityads.unity3d.com/ you can make an Unity ads account and add your game and you will be asked to fill in some information about your app. In the dashboard you will see your app and your game ID just replace YOUR GAME ID HERE with your game ID.