Configuration – Settings
On the Configuration-Settings page you can select the method by which the plugin will figure out what is the country of your visitor. You can also choose if you want the crawlers/robots to see your restrictions and what crawlers to allow to do that.
To do that you will have to go to: https://developers.facebook.com/apps/ and click on the Register Now button. Continue the process and once you get the Application ID, input it in the plugin.