How do I change scenes using a GUI button in unity 5.1

I would like to create a title screen for my current game and being new to c# and Unity in general I would like to change scenes after pressing on a button. If possible I would like this in C# rather than javascript or boolean. (P.S. I own a 4GB Macbook Air running El Capitan with a 1.4GHz i5 processor.)

if (GUI.Button(new Rect(10, 10, 50, 50))

Put this in your OnGUI(). “sceneName” is the name of the scene you want to load.