How to Wrestle Down GUIs in Unity 3D

using UnityEngine;
using System.Collections;
using System; //Necessary to access Action
 
/// <summary>
/// An example for using delegates to show different menu screens.
/// </summary>
public class DelegateGUI : MonoBehaviour {
 
    #region Setup
 
    /// <summary>
    /// The delegate that is going to be used.
    /// </summary>
    private Action OnGUIMethod;
 
    /// <summary>
    /// The standard GUI method, as inherited by MonoBehaviour.
    /// </summary>
    private void OnGUI () 
    {
        if (OnGUIMethod != null) {
            OnGUIMethod();
        }
    }
 
    /// <summary>
    /// Define what screen to show first.
    /// </summary>
    private void Start () {
        OnGUIMethod = Screen1;
    }
 
    #endregion
 
    #region Screens
 
    /// <summary>
    /// A very simple function that will theoretically show two buttons,
    /// which in turn show the other screens. The following functions
    /// work similarly.
    /// </summary>
    private void Screen1 () {
        // Show all that appears on the first screen – some Buttons might do
 
        if (GUI.Button(/* GUI.Button stuff comes here */)) {
            // Do stuff here
            OnGUIMethod = Screen2;
        }
 
        if (GUI.Button(/* GUI.Button stuff comes here */)) {
            // Do stuff here
            OnGUIMethod = Screen3;
        }
 
    }
 
    private void Screen2 () {
        // Show all that appears on the second screen – some Buttons might do
 
        if (GUI.Button(/* GUI.Button stuff comes here */)) {
            // Do stuff here
            OnGUIMethod = Screen3;
        }
 
        if (GUI.Button(/* GUI.Button stuff comes here */)) {
            // Do stuff here
            OnGUIMethod = Screen1;
        }
    }
 
    private void Screen3 () {
        // Show all that appears on the third screen – some Buttons might do
 
        if (GUI.Button(/* GUI.Button stuff comes here */)) {
            // Do stuff here
            OnGUIMethod = Screen2;
        }
 
        if (GUI.Button(/* GUI.Button stuff comes here */)) {
            // Do stuff here
            OnGUIMethod = Screen1;
        }
    }
 
    #endregion
}