Ad Mediation Plugins is using Admob implementation from the Google Mobile Ad plugin which is part of Stan's Assets products. In order to enable Admob Network you need to ownGoogle Mobile Ad plugin copy, which can be purchased from the Asset Store.
So set up steps would be:
- Import Google Mobile Ad plugin to your project.
- Setup the Admob account.
- Enable AdMob Network in plugin settings as showed on the screenshot bellow.
Once you done with the Setup, you may use AdMob Network in your Mediation Profile.