Here is a simple example how can you use the GUILayout and display a text.

function OnGUI() {
    GUILayout.BeginArea(Rect(128, 128, 256, 256));
    GUILayout.Box("Foo");
    GUILayout.Label("Bar");
    GUILayout.TextArea("Hello, world!");
    if (GUILayout.Button("Awesome")) {
        //Do something awesome!
    }
    GUILayout.EndArea();
}

If you love learning more, just go through GUI Scripting Guide . It will help you a lot.