How to get the GUI buttons to render properley

I have made a main menu for my game and i want it to render the gui buttons properly without changing scenes. I have set it up just to show you that every time it says, Example -- then it lists off a few gui buttons for the next one. Every one of these i want to only display those buttons when activated. Here is an example of the code:

using UnityEngine; using System.Collections;

public class NeonHub : MonoBehaviour {

 public float rightAndLeftQuit;

 public float upAndDownQuit;

 public GUIStyle Quit;

 public float rightAndLeftStageSelect;

 public float upAndDownStageSelect;

 public GUIStyle stageSelect;

 public float rightAndLeftUpgradeCenter;

 public float upAndDownUpgradeCenter;

 public GUIStyle upgradeCenter;

 public float rightAndLeftOptions;

 public float upAndDownOptions;

 public GUIStyle Options;

 public float rightAndLeftTitle;

 public float upAndDownTitle;

 public GUIStyle title;

 public bool stage = false;

 public bool options = false;

 public bool center = false;

 public bool main = true;

 public bool play = false;

 public bool multi = false;

 public float rightAndLeftSlider;

 public float upAndDownSlider;

 public GUIStyle slider;

 public float rightAndLeftPlay;

 public float upAndDownPlay;

 public float rightAndLeftMulti;

 public float upAndDownMulti;

 public float rightAndLeftBack;

 public float upAndDownBack;

 public GUIStyle Play;

 public Texture background;

 // Use this for initialization
 void Start () {
     PlayerPrefs.SetInt ("main", 1);
 
 }
 
 // Update is called once per frame
 void Update () {

     if(Input.GetKey(KeyCode.Escape)){
         Application.Quit();
     }
 }

 void OnGUI(){
     //title
     GUI.Box(new Rect (Screen.width * rightAndLeftTitle, Screen.height * upAndDownTitle, Screen.width * .2f, Screen.height * .4f), "Neon Wars", title);
     //levels of the main menu
     Main Hub --

         if (GUI.Button (new Rect (Screen.width * rightAndLeftQuit, Screen.height * upAndDownQuit, Screen.width * .18f, Screen.height * .1f), "Quit Game", Quit)) {
                 Application.Quit ();
         }
         if (GUI.Button (new Rect (Screen.width * rightAndLeftPlay, Screen.height * upAndDownPlay, Screen.width * .18f, Screen.height * .1f), "Play Game", Play)) 
         {
             PlayerPrefs.SetInt ("menu", 2);
         }
         if (GUI.Button (new Rect (Screen.width * rightAndLeftUpgradeCenter, Screen.height * upAndDownUpgradeCenter, Screen.width * .18f, Screen.height * .1f), "Upgrade Center", upgradeCenter)) 
         {
             PlayerPrefs.SetInt ("menu", 3);
     
         }
         if (GUI.Button (new Rect (Screen.width * rightAndLeftOptions, Screen.height * upAndDownOptions, Screen.width * .18f, Screen.height * .1f), "Options", Options)) 
         {
             PlayerPrefs.SetInt ("menu", 4);
         }


 Play Game Tab --

         if (GUI.Button (new Rect (Screen.width * rightAndLeftStageSelect, Screen.height * upAndDownStageSelect, Screen.width * .18f, Screen.height * .1f), "Stage Select", stageSelect)) 
         {
             PlayerPrefs.SetInt("menu", 5);
         }

         if (GUI.Button (new Rect (Screen.width * rightAndLeftMulti, Screen.height * upAndDownMulti, Screen.width * .18f, Screen.height * .1f), "Multi-Player", upgradeCenter)) 
         {
             PlayerPrefs.SetInt("menu", 6);
         }

         if (GUI.Button (new Rect (Screen.width * rightAndLeftBack, Screen.height * upAndDownBack, Screen.width * .18f, Screen.height * .1f), "Back", upgradeCenter)) 
         {
             PlayerPrefs.SetInt("menu", 1);
         }
     }

     Level Select -- 

         if (GUI.Button (new Rect (Screen.width * rightAndLeftUpgradeCenter, Screen.height * upAndDownUpgradeCenter, Screen.width * .18f, Screen.height * .1f), "Level 1", upgradeCenter)) {
             Application.LoadLevel("Level1");
         }
         if (GUI.Button (new Rect (Screen.width * rightAndLeftBack, Screen.height * upAndDownBack, Screen.width * .18f, Screen.height * .1f), "Back", upgradeCenter)) 
         {
             PlayerPrefs.SetInt("menu", 1);
         }
     }

 Options Menu -- 


         if (GUI.Button (new Rect (Screen.width * rightAndLeftBack, Screen.height * upAndDownBack, Screen.width * .18f, Screen.height * .1f), "Back", upgradeCenter)) 
         {
             Display main buttons
         }
     }
     UpgradeCanter --
                     if (GUI.Button (new Rect (Screen.width * rightAndLeftUpgradeCenter, Screen.height * upAndDownUpgradeCenter, Screen.width * .18f, Screen.height * .1f), "Upgrade", stageSelect)) {
         }
         if (GUI.Button (new Rect (Screen.width * rightAndLeftBack, Screen.height * upAndDownBack, Screen.width * .18f, Screen.height * .1f), "Back", upgradeCenter)) 
         {
             Display main buttons
         }
     }
 Multiplayer Random Match --
                     if (GUI.Button (new Rect (Screen.width * rightAndLeftUpgradeCenter, Screen.height * upAndDownUpgradeCenter, Screen.width * .18f, Screen.height * .1f), "Random Match", stageSelect)) {
         }

         if (GUI.Button (new Rect (Screen.width * rightAndLeftBack, Screen.height * upAndDownBack, Screen.width * .18f, Screen.height * .1f), "Back", upgradeCenter)) 
         {
             Display Play
         }
     }
 }

}