Admob - Unity Ads Mediation

So, I've done all the necessary setup at Admob website to configure Unity Ads. Set the public key, game id and zone id.

But I'm not being able to show the videos in my device.

I'm aware that I need to import some .jar and .aar files, but every guide I follow it doesn't work.
Yes, I'm using Admob, but I'm trying to mediate it through Unity Ads. So, I posted this same question in both Admob and Unity Forums.

Hope you guys can give me some tips on how to do it.

Thanks