How to Download the Facebook App on Your Samsung Galaxy S 4
Tap the Accept button.
Before the download process starts, your app may want to know two things. First, do you want your phone to automatically update when Facebook (or the app provider) releases a newer version? In general, this is the most convenient option. It is rare, but not unheard of that an update makes things worse.
The second is whether you want to wait for the update to take place only when you have a Wi-Fi connection. This prevents your phone from downloading a huge application update over the cellular network. In most cases, using a Wi-Fi connection is a better option. Facebook asks you this question in the pop-up.