How do I access "System Settings" in Ubuntu 15.04?
System Settings if present by default as a shortcut in Ubuntu taskbar :
If you don't have this shortcut you can open it by doing :
Command line way :
Open a terminal (Ctrl+Alt+T) and type :
unity-control-center
Graphical way :
Open Unity dash (click on the Ubuntu logo on the taskbar or use the 
key of your keyboard) and search for "System Settings" :
Click the wheel in the top right corner of the panel and then select System Settings.
