How to make buttons have sound when it is highlighted and clicked?

I also want the sound when it's highlighted to be different from the sound when it's clicked. So I first got two different sounds and named them Highlighted and Clicked.Next, I added them as audio sources to a button named 1-player.Then, I made a script named Button and typed the following in it.

using UnityEngine; using UnityEngine.UI; using UnityEngine.EventSystems; using System.Collections;

public class Button : MonoBehaviour, IPointerEnterHandler,IPointerDownHandler { private AudioSource audioSource; public AudioClip Clicked; public AudioClip Highlighted;

 public void OnPointerEnter(PointerEventData ped) {
     audioSource.Play (Clicked);
 }
 
 public void OnPointerDown(PointerEventData ped) {
     audioSource.Play (Highlighted);
 }

}

Note: I copied someone else's code that was in response to a question similar to mine.I changed some of it because my methods and functions were different from the person's (which caused compiler errors.)However, even after changing the code, I still have compiler errors.Can anyone please tell me how to fix my code (or fix or change anything) so that when I highlight and click my button it will produce sound? Any help will be greatly appreciated!