How to add Muzzle Flash to Weapon

I have a functional Weapon but i cant get an Muzzleflash atached to it can someone tell me how? here my Weapon script:

 //the bullet we are shooting must have a rigidbody 
 var Bullet : Transform;
 //the speed the bullet is shot at
 var Speed = 16000;
 //where the bullet spawns (most likely the tip of the gun)
 var spawnPoint : Transform;
 //if we shoot like a machinegun or not
 var RapidFire = false;
 //if we shoot every click or not
 var SingleFire = true;
 //this is only used if rapid fire is set to true
 private var shooting = false;
 //RateOfFire private
 var Counter = Time.deltaTime;
 var RateOfFire = 0.250000;
 
 function FixedUpdate () 
 {
 //if single fire is set to true
 if(SingleFire==true){
 //we are using the left mouse button to shoot
 if(Input.GetButtonUp("Fire1")){
 //we create the bullet
 var shot =Instantiate(Bullet, spawnPoint.transform.position, Quaternion.identity); 
 //we add the speed 
 shot.rigidbody.AddForce(transform.forward * Speed); } }
 if(RapidFire ==true){
 if(Input.GetButtonDown("Fire1")){
 shooting=true;
 }
 if(Input.GetButtonUp("Fire1")){
 shooting=false;
 }
 if(shooting==true){ Counter += Time.deltaTime;
 if(RateOfFire
 <
 Counter){
 var shotRapid =Instantiate(Bullet, spawnPoint.transform.position, 
 Quaternion.identity); 
 //we add the speed 
 shotRapid.rigidbody.AddForce(transform.forward * Speed); 
 Counter=0; } } } }