We’ll choose the interstitial ad format to create our ad unit. Select “Interstitial” and on the next screen, give a name. Then, we are done. In the final screen, we’ll be given two IDs—an app ID and an ad unit ID. Right now we just need the app ID, so copy it.

Once we have finished creating our ad unit, we’ll see a screen like the one below:

Ad unit

Ad unit

If you forgot to copy the app ID, you can get it by clicking on the ad unit and then on “Implemented Instructions.” Now we have to tell our Flutter app that we’ll be using AdMob. So to do that, we have to do two things.

First, take the following line of code containing the app ID and paste it inside the of your AndroidManifest.xml file found under /android/app/src/main. Replace APPLICATION_ID with the app ID.