If you still can not find it Click Here to go directly to Facebook Create Page Screen (Make sure you are signed in Facebook).
Creating a new Facebook Page
On Create a Page screen you will be asked to enter various information to input. You can choose between Official Page or Community Page. When you create a page you will see URL in Browser address bar for that page. As highlighted below in screenshot you need to copy your Page ID and paste in settings of the extension.
Customized Facebook Page ID
If you have customised Facebook Page URL then your ID will not show in URL and your URL will be like http://www.facebook.com/USER_NAME instead. To find your Facebook Page ID from a Customised URL simply go to your Facebook home page (http://www.facebook.com) and click on Ads and Pages. This will take you to pages screen where you should be able to see Page ID in URLs.
To delete a Facebook Page:
Click "Edit Page" underneath the profile picture when viewing your Page.
Select "Manage Permissions" from the left sidebar.
Click "Permanently delete this Page." Please keep in mind that once you delete your Page, there's no way to reinstate it.