Facebook app disappeared from iPhone

I have a problem that someone previously described, but the solution didn't work for me. My Facebook app has disappeared from my phone, though the phone still seems to have it available as an app that I can open when I go to the app store. The advice I saw said to go to setting, general, and look under "usage" but I don't have that as an option on my phone. Then I'm supposed to delete the app and reload. I can't find anywhere else where deleting the app is an option.