timer change scene unity

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

public class SceneTimer : MonoBehaviour
 {
     // can be set in the Inspector for this script
     public string sceneName;
         // alternatively, you can do something like
         // public const string sceneName = "SecondScene";
 
     // time after this script initializes, in seconds,
         // that the scene transition will happen
     public const float TIME_LIMIT = 5F;
 
     // timer variable
     private float timer = 0F;
         // alternatively, you can set this in an Awake() function,
         // which is automatically called when the script initializes
 
     // automatically called many times every second
     void Update()
     {
         // deltaTime is the time (measured in seconds) since the previous Update step
         // it's typically very small, e.g. 1/60th of a second ~= 0.0167F
         this.timer += Time.deltaTime;
 
         // check if it's time to switch scenes
         if (this.timer >= TIME_LIMIT)
         {
             SceneManager.LoadScene(sceneName);
         }
     }
 }