This is how to fix an app that didn't appear when you first downloaded it. This happened to me and don't know how many people have had this problem.
Step 1: App Not Appering
So I downloaded tumblr and the app icon didn't appear. So I thought I might share how to fix that.
Step 2: First
Go to your settings.
Step 3: Second
Go to general
Step 4: Third
Go to usage and click show all apps.
Step 5: Forth
Find the app and click on it then delete it
Step 6: Finally
Re-download the app and it will appear