In order to reveal an application on your iPhone’s Home Screen (the desktop), first slide left passing your last Home Screen page and check the App Library. Later on, find the app and then tap and hold its icon. Go to the menu and hit the add to home screen.
Tap and hold an empty piece of the Home Screen, until the apps jiggle, if you've hidden a Home Screen page. Turn to the dots at the bottom, and now unclick the circle to the left of the hidden page to unhide it. Tap "Done".