Implementing iAd in Unity games

After hours of searching for a definitive answer, I am still in the dark as to how to implement iAd banners in Unity iOS games. The game in question is already on the app store, however I will update it with more content and ads, however I have no idea how to get iAd in Unity. My iTunes connect has iAd enabled for the game, however I have no idea what coding I need to use and where to put it (Unity or XCode). I have tried using the coding provided in the ADBannerView documentation provided by Unity, however it comes up with many compiling errors all of which are beyond my understanding. Any ideas?

Thanks

There is an example in HELP when you search for AdBannerView. I managed to make the ad show in the test build on my iPad, but Apple rejected my game because they could not see the ad. So, now I’m also wonder whether my implementation is correct or not.