|Step by Step: How to create a Facebook Application ID|
This guide was made on 24th of June, 2012. So any later change on the Facebook Developers page may not be included.
1. Go to Facebook Developers's Apps page, you may have to login to access this page. Note: you have to use a personal account.
2. Click the button.
3. In the upcoming window, add an App Name, which may be the name of your site.
4. Clear the "Security Check Required" window by submitting the required text.
5. Now you will already see the generated AppID on the top of your page.
6. Now you will have to link your site to this AppID. First click on Website with Facebook Login.
7. Enter your Site URL.
8. Now add this same URL to the App Domains under Basic Info.
9. Click the button.
10. You are done, you can find you AppID on the top of the page as 5. shows.
Obviously you can add more information of your site if you wish, howver this is the absolute minimum required by the plugins to work.