How does it work?
Step 1 - Click on "Business App Connecting Page" link in the banner at the top of the screen.
Step 2 - The link will lead to Settings → Connect Accounts
Step 3 - Click "Continue as" account.
Step 4 - After clicking “Continue as” select all pages even if only one or two of the pages is desired for connection as this is a MUST ask from Meta. Then click “Next” as shown below.
Step 5 - After clicking “Next” turn on all as this is required by Meta. Then click “Done” and click “OK” on the next screen.
Step 6 - After clicking "OK" the user will be redirected back to Business App as shown below where the user can select the Facebook page required to connect.