In this section, we are going to modify our Android manifest in order to insert it in the required configuration for using the Google Play Services library.

We just need to add two snippets, one of which will be just next to the opening application tag that will indicate the version of the Google Play Services being used, as we can appreciate in the following code listing:

        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />

The second snippet that we are going to add is the AdActivity declaration, which will be added just next to the declaration of our game activity, so that our game is aware of this built-in activity located in the Google Play Services library:

       <activity
            android:name="com.google.android.gms.ads.AdActivity"
            android:configChanges="keyboard|keyboardHidden|orientation| screenLayout|uiMode|screenSize|smallestScreenSize...