What is wrong with my code?

I was following the survival shooter tutorial on unity's website for their health and damage scripts so I can learn how to do it. So I followed it I understood it until when I completed the scripts I got an error: (42,34) CS0120 An object reference is required to access non-static member DamageHandler.currentHealth
(43,39) CS0120 An object reference is required to access non-static member DamageHandler.Damaged(int) The thing I can't figure out is why is it saying I have not referenced it I did that in void awake.

Here is my code if you want to look:

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 public class DamageHandler : MonoBehaviour {
 
     public int startingHealth = 100;
     public int currentHealth;
 
     public float flashSpeed = 5f;
     public Color flashColour = new Color(1f, 0f, 0f, 0.1f);
 
     public Slider healthSlider;
     public Image damageImage;
 
     bool isDamaged;
     bool isDead;
 
     void Awake(){
         currentHealth = startingHealth;
     }
 
     void Update(){
         if (isDamaged) {
             damageImage.color = flashColour;
         } else {
             damageImage.color = Color.Lerp (damageImage.color, Color.clear, flashSpeed * Time.deltaTime);
         }
         isDamaged = false;
     }
 
     public void Damaged (int amount) {
         isDamaged = true;
 
         currentHealth -= amount;
 
         healthSlider.value = currentHealth;
 
         if(currentHealth <= 0 && !isDead) {
             Death ();
         }
     }
 
     void Death() {
         isDead = true;
         Destroy (gameObject);
     }
 }




 using UnityEngine;
 using System.Collections;
 
 public class EnemyShooting : MonoBehaviour {
 
     public float attackDelay = 0.5f;
     public int attackDamage = 10;
 
     GameObject player;
     DamageHandler damageHandler;
     bool playerInRange;
     float timer;
 
     void Awake () {
         player = GameObject.FindGameObjectWithTag ("Player");
         damageHandler = player.GetComponent<DamageHandler> ();
     }
 
     void OnTriggerEnter2D (Collider2D other) {
         if (other.gameObject == player) {
             playerInRange = true;
         }
     }
 
     void OnTriggerExit2D (Collider2D other) {
         if(other.gameObject == player) {
             playerInRange = false;
         }
     }
 
     void Update () {
         timer += Time.deltaTime;
 
         if (timer >= attackDelay && playerInRange) {
             Attack ();
         }
     }
 
     void Attack () {
         timer = 0f;
 
         if(DamageHandler.currentHealth > 0) {
             DamageHandler.Damaged (attackDamage);
         }
     }
 }