Press and hold your finger on the right hand side of the home screen.

From the pop-up menu, select Add bubble.

User-added image

Tap Generic app.

Search for the app that you want to add from the list of installed apps and click to select it. 

The app will be automatically be added to your Quick Launcher. 

To remove a bubble from the Quick Launcher, press and hold its icon and select Remove. Please note, this does not uninstall the app from the device.