In the upper Right hand corner you should have a small icon labeled Apps and a + next to it. If you don't see this (you see the screens that have tables with shelf under it) there is a +. Pressing either the Apps or the +, depending on what you use as home screens, you should find the listed apps and can then add them. If you go in through apps, long press the app to set it on the desired screen. Go in through the +, put a check on the apps you want to add.