Tappy Chicken has no ads

Hello, I want to ask if Tappy Chicken downloadable from the Google Play store can show adverts. I’ve downloaded Tappy Chicken a week ago and tried it.
It doesn’t show ads, but it shows the leaderboard and the achievements perfectly. I’ve also tried to compile and use the Tappy Chicken Project available on the Marketplace. Even the compiled Tappy Chicken doesn’t show adverts on my device.
What is the correct way to set up my game for Admob?

I managed to have ads in my applications by changing the Engine source code.

Care to share? Would be good to know

See this video ADMOB Unreal Engine 4: