Tap the button (the square with an arrow) and select "Add to Home Screen."
A pop-up will appear saying the latest version is not compatible. Select to get the last version that works with iOS 12. Method 2: The "Newer Device" Trick Download Facebook Ios 12-5-7
Tap the Share icon and select "Add to Home Screen" to create a shortcut that acts like an app icon. Tap the button (the square with an arrow)