How to make Health bar ?

This is what I'm used for a while before i made my GUI more dynamic(it's a c# script). It's a Modified script of the BurgZerg Arcade. Although you can find his good tutorials here: http://www.burgzergarcade.com/hack-slash-rpg-unity3d-game-engine-tutorial

First though you need to have 2 images, one of the gui like that and one separate bar for the health.

Here's the code:

 using UnityEngine;
 using System.Collections;
 
 public class health : MonoBehaviour {
         public GUIStyle PlayercurhealthplaceH;
     public GUIStyle Playercurhealthtext;
         public int MaxHealth = 320;
     public int CurHealth = 320;
     public float HealthBarLength;
 
     
         void start(){
         
     HealthBarLength = 200;    
         
     }
     
     void OnGUI(){
         //Heath bar
           
         //This is where you put the background image
          GUI.Box(new Rect((Screen.width /2) -339,(Screen.height /2) +300,200,20),"", PlayercurhealthplaceH);    
         //This is where you put the foreground image, the green bar by itself.
         GUI.Box(new Rect((Screen.width /2) -339,(Screen.height /2) +300,200/(MaxHealth/CurHealth),20), CurHealth + "/" + MaxHealth, Playercurhealthtext);
           
     }
     
         public void AdjustCurrentHealth(int Adj){
     
         CurHealth += Adj;
         
         if (CurHealth <0)
             CurHealth = 0;
         if(CurHealth > MaxHealth)
             CurHealth = MaxHealth;
         if(MaxHealth < 1)
             MaxHealth = 1;
             
         HealthBarLength = (200) * (CurHealth/(float)MaxHealth);
         
         
         
     
     }
     
     
     public void update() {
     
          AdjustCurrentHealth(0);
         
     
     
 }
 

Now you'll be expected to know how to use the inspector to add the images ect yourself. I hope this helped. If your still confused, keep your image, watch burgzerg's videos and eventually when your knowledge of coding goes up, he also goes into detail on how to add GUI, but practice coding first!