I have created a landing/welcome page for a new client and the process seems to have changed. I can no longer go to the application profile to add it to the page. I was able to locate instructions through a google search that involved the following link:
https://www.facebook.com/dialog/pagetab?app_id=YOUR_APP_ID&display=popup
I replaced "popup" with what I thought was my canvas and I replaces "YOUR_APP_ID" with my app id taken from the settings. I get API Error Code: 100 API Error Description: Invalid parameter Error Message: Requires valid redirect URI.