For most people, the entire purpose of a Home screen is displaying app icons. But there are no icons on Facebook’s Home screens; Facebook thinks you’d rather use that space for reading Facebook updates.
The only icon that appears is your own profile photo. You can drag it to the left to open the Facebook Messaging app, to the right to open the last open app — or upward to open a grid of app icons on a gray background. Ah, here are the apps. But it’s awfully sparse; where are the rest?
They’re on a screen off to the left. Swipe your finger to see, on a black background, the usual Android “all apps” screen. From here, you can hold your finger down on a particular app’s icon to install it onto the gray-background launcher screen, which can have multiple pages.
If it sounds confusing, that’s because it is. In removing the app-launching function from the Home screen, Facebook has wound up having to reinvent the way you open programs on your phone, and the result feels like a hack.