Just adding to the database.
Here is a screen shot of a properly setup AdMob event
Yes, I tested it and it works :)
I use a boolean "adReward" to test if the player has been rewarded for a video already (if yes, then I don't spawn an ad)
On Video complete, I set the adReward boolean to True. This is the event trigger I use to apply the in-game reward or not. After the player uses the reward, the boolean is set back to false, and a new ad can load when they revisit the game's town hub.
Edit: Before anyone asks, you must wait for your adMob account to be verified (usually 24hours) before even test ads will spawn in your project.