Here is our first example of ineffective Facebook instructions regarding adding an App to a Facebook page ...
facebook.com/help/?faq=172925542764476 (link to the ineffective instructions)
How can I add apps to my Facebook Page?
To add an app to your Facebook Page, first go to the App About Page for the app you'd like to add. If the app is available to be added to your Page, you'll see an Add to Page link on the lower left-hand column.
Note that certain apps may not be available for Pages. If you have any questions about those apps, please use the Contact Developer link in the App About Page to inquire.Unfortunately, there is no Add to Page link in the lower left-hand column. So we attempted to find the app's fan page instead, to see if the app could be added from the fan page. We recalled that used to work.
Here is the set of instructions from Facebook on how to find the app's fan page.
How do I find an app's fan page?
The app's fan page is where you can access the app, contact the developer, block the app and more.
To find an app's fan page,
1. Return to your home page by clicking Back to Facebook at the top right corner of the Help Center
2. Enter the name of the app in search
3. Select the result under the Pages heading
4. This result is the app's fan page
Unfortunately searching for an app that was created by the developer can result in the link being discovered, but the link refers the user to this ...
The page you requested was not found.You may have clicked an expired link or mistyped the address. Some web addresses are case sensitive.stackoverflow.com found a solution for navigating to the APP PROFILE PAGE or APP FAN PAGE that gets the user or developer to that place necessary to add an app to a Facebook fan page. Stackoverflow.com was working on an issue with Facebook where newly created App Profile Pages could not be found after a basic page tab app was created. After creating the app, a use would click the View App Profile Page link and get the error message "The page you requested was not found". Fortunately, a workaround was discovered. But first you have to know your app's ID.
Go back to the previous page
Go to developer.facebook.com
Click on Apps in the upper right of the page (in the blue bar) ... Next, you will see a list of your Apps in the left column.
Select the App that you want to add to your Facebook fan page.
In the summary section, note the number under App ID/API Key and open another browser window (you will copy the App ID later).
[NOW FOR THE HELP FROM STACKOVERFLOW.COM]
The following link discovered by stackoverflow.com gets a user to the APP PROFILE PAGE that allows the user to add the app to a Facebook page.
Paste the link above into your browser's URL address field (new window). But DON'T HIT ENTER, YET.
Now go copy the APP ID from earlier-opened browser window.
Replace [APP-ID] with your App's App ID number (get rid of the brackets [ ] too) in the second browser window you opened.
Hit enter, and you should see ...
Add Forecast?Add this application to:
[DROP DOWN MENU TO SELECT PAGE WHERE YOU WANT APP]
Adding Forecast will let it pull your page's profile information, photos, friends' info, and other content that it requires to work. It will also add a box to your page and can publish Feed stories about your page.
One more quirk from Facebook ...
After you select the page to install the app (from the drop down menu), most users are taken to a confusing "results" page ...
Forecast is under construction. Please try again later.Forecast is under construction. Please try again later.
Message for Developers Only:
To fix this error, please set your Canvas Callback URL in the application settings editor [LINK]. Once it has been set, users will be redirect to that URL instead of this page after logging in.
Don't worry, the App should be installed. However if you follow the link to the application setting editor, there is no Canvas Callback URL setting to be found.
Hopefully this will all be fixed someday.
See also ...
stackoverflow.com unable to view APP PROFILE PAGE … “The page you requested was not found”
A similar bug or problem may have caused a problem affecting the permissions dialog procedure for apps such as RSS Graffiti
See Missing Permissions - Solutions Guide