Unity Ads in Unity 5.2

Hello,

I'm having trouble getting Unity Ads to work in Unity 5.2.
I've looked at so many tutorials and can't get it to work.

I'm wanting to make the ads appear at game over. Where abouts would I add the sample code into my script?
This is my script so far. But have had no success.


using UnityEngine;
using UnityEngine.Advertisements;
using System.Collections;

public class SimpleAds : MonoBehaviour
{
public void ShowAd()
{
if (Advertisement.IsReady())
{...

Unity Ads in Unity 5.2