How to add MuzzleFlash?

Hey guys I'm 11 so clearly, I'm a beginner, but I've learned all those basic stuff and trying to make a FPS now, I've been learning Instantiating and Raycast and I decided to use raycast but the problem now is that I can't add the MuzzleFlash, whenever I add it, the Muzzleflash never appear, what should I do? Here's my script :

using UnityEngine; using System.Collections;

public class Gun : MonoBehaviour { public enum FireMode { Auto, Burst, Semi }

 //Changing the firemode
 public FireMode firemode = FireMode.Auto;

 //RPM and firerate
 public float FireRate = 0.05f;
 public float FireTime;
 public bool IsBurst = false;
 
 void Update()
 {
     if (FireTime <= 0 && !IsBurst)
     {
         switch (firemode)
         {
             case FireMode.Semi:
             if (Input.GetButtonDown("Fire1"))
             {
                 Fire();
                 GetComponent<AudioSource>().Play();
                 FireTime = FireRate;
             }
             break;

             case FireMode.Burst:
             if (Input.GetButtonDown("Fire1"))
             {
                 StartCoroutine(BurstFire(FireRate, 3));
                 GetComponent<AudioSource>().Play();
                 FireTime = FireRate;
             }
             break;

             case FireMode.Auto:
             if (Input.GetButton("Fire1"))
             {
                 Fire();
                 GetComponent<AudioSource>().Play();
                 FireTime = FireRate;
             }
             break;
         }
     }
     if (FireTime > 0)
     {
         FireTime -= Time.deltaTime;
     }
 }

 void Fire()
 {
     RaycastHit hit;
     Ray ray = new Ray(transform.position, transform.forward);
     if (Physics.Raycast(ray, out hit, 100f))
     {

     }
 }

 IEnumerator BurstFire(float rate, int rounds)
 {
     IsBurst = true;
     for (int i = 0; i < rounds; i++)
     {
         Fire();
         yield return new WaitForSeconds(rate);
     }
     IsBurst = false;
 }

}