In order to connect your mono Facebook site app to your Facebook company/fan page you must be an administrator of the page. Assuming this is in order follow the steps below.
1. In the FACEBOOK tab in the mono tool, click "Setup your Facebook connection" in the right-hand corner of the edit view.
2. A pop up will appear. Follow the instructions.
3. Facebook will likely ask you for permission to connect to your Facebook profile to access your pages. You must accept this in order to connect the app to your page.
4. Choose the Facebook page to which you'd like to connect.
5. Publish your mono Facebook site when you're ready to go live.