Unity fan integration

Hi everybody

i try to integrate FAN into my unity games.

But i can not see any Interstitial ad. what is the problem?

my app was approved and i am following instructions in FAN manual that was saying

"

Import FBAudienceNetwork.dll into your Unity project, and add everything under Plugins to your Asset folder.
Android users may need to edit the Plugins/Android/AndroidManifest.xml.
Platforms other than iOS and Android are not supported.

"

where is the file FBAudienceNetwork.dll?

i just imported “facebook-unity-sdk-7.4.0\facebook-unity-sdk-7.4.0\AudienceNetworkSDK”.

i added also

"
<activity android:name=“com.facebook.ads.InterstitialAdActivity” android:configChanges=“keyboardHidden|orientation|screenSize” />
"

into my androidmanifest.xml .

and what can the problem be?

thanks in advance.