Making the delay actually work

I have a delay in my code now, but it is not waiting the amounted seconds I had assigned it. What do I do know?

The Codes I added are on lines 11-13 and 51-55

Do I have to add something in the middle or add something else to the IEnumerator?

Here is the Code:

 using UnityEngine;
 using System.Collections;
 
 public class PlayerHealth : MonoBehaviour {
     public int maxHealth = 100;
     public int curHealth = 100;
     public Transform target;
     
     public float healthBarLength;
     
      IEnumerator Do() {
         yield return new WaitForSeconds(2);
     }
    
 
     
 
     // Use this for initialization
     void Start () {
         healthBarLength = Screen.width / 2;
         
          animation["death"].wrapMode = WrapMode.Once;
               animation["death"].layer = 1;
     
     }
     
     
     // Update is called once per frame
     void Update () {
         AddjustCurrentHealth(0);
     
     }
     
     void OnGUI() {
         GUI.Box (new Rect(10, 40, healthBarLength, 20), curHealth + "/" + maxHealth);
     }
     
     public void AddjustCurrentHealth(int adj) {
         curHealth += adj;
         
         if(curHealth < 0)
             curHealth = 0;
         
         if(curHealth > maxHealth)
             curHealth = maxHealth;
         
         if(maxHealth < 1)
             maxHealth = 1;
         healthBarLength = (Screen.width / 2) * (curHealth / (float)maxHealth);
         
         if(curHealth <= 0){
                animation.Play ("death");
                 Do();
                     Application.LoadLevel(2);
         
         }
         
 }
 }