How do I configure ad Mediation in the AdMob Plugin?

As the question says, I want to add more Ad Networks into my AdMob account. But every network talks about adding their SDK into the Android project.

I use Intel XDK to build my APK, so how do I add the other Ad SDKs and the Ad units into a Construct 2 project?

I already have 15,000+ downloads but the revenue is sometimes below $1 :'(

Any help is really appreciated.

(Game link in my signature)