,Switch Scenes Error

Lately I’ve Been Working On A Video Game And I Can’t Seem Too Get The Switching Scenes With A Button To Work I Have Tried Nearly Everything Too Old Unity Scripts Too New Unity Scripts And The Most Relevant Fix And Script Videos. This Really Makes Me Upset Because I Always Wanted To Make A Main Menu And It Just Never Works It Always Gives Me Red Underlines Especially The Scenemanger or LoadScene Error And Yes I Have Done All The Fixes For It If Someone Could Help Me That Would Be Great And Amazing Thanks!,Lately I’ve been working on a game and I just can’t figure out how to switch scenes I have tried almost everything to old unity scripts to the most relevant so nothing as been working for switching scenes and I really need help it would be awesome to know one script actually works btw the scenemanager I’ve looked at all the videos to fix it however it still doesn’t work.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

public class MyChangeScene : MonoBehaviour {

	// Use this for initialization
	void Start () {
		
	}
	
	// Update is called once per frame
	void Update () {
		
	}

	public void ChangeSceneWithName(string sceneName)
	{
		SceneManager.LoadSceneAsync (sceneName);
	}
	public void ChangeSceneWithIndex(int sceneIndex)
	{
		SceneManager.LoadSceneAsync (sceneIndex);
	}
}