Unity own ingame UI

[Sub7]

I have created an example with ingame ui (user interface) in which you can select each game object in the game and change the parameters (position, scale, visible or not, etc.)

Own scene:

• example Image
  http ://i.imgur.com/Xj48psG.png (Empty place of the link)
• example .exe

In unity real game:

If I want to spend with reflector/reflexil simple hello world I see no changes in the game, I have to assign it to an object right?
How do I do this in the reflector?

using UnityEngine;
using System.Collections;

public class test : MonoBehaviour
{
    
    void OnGUI()
    {
        GUIStyle style = new GUIStyle();
        GUI.Label(new Rect(100, 100, 100, 20), "<size=20><color=brown>Hallo World</color></size>", style);    }
}