when testing in the game mode , shots don't fire ?

iam following the official unity space shooter tutorials but in 2d space/orthographic setup and my player is just a 2d sprite/.png

the shots fire only when i drag the shot prefab into heirarchy in game mode.. its very frustrating

this is the player/jet script :

using UnityEngine; using System.Collections; [System.Serializable] public class Boundary { public float xMin,xMax,yMin,yMax; } public class PlyrScript : MonoBehaviour { public float speed; public Boundary boundary; public GameObject shot; //linked the bullet/projectile prefab in the shot parameter public Transform shotSpawn; // linked the transform of the shotspawn gameobject to it public float fireRate; private float nextFire; void update () { if (Input.GetButton("Fire1")) && Time.time > nextFire) { nextFire = Time.time + fireRate; //GameObject clone = //print("space key was pressed"); Instantiate(shot, shotSpawn.position, shotSpawn.rotation); } } void FixedUpdate () { float mHzntl = Input.GetAxis ("Horizontal"); float mvrtcl = Input.GetAxis ("Vertical"); Vector3 movement = new Vector3 (mHzntl, mvrtcl, 0.0f); rigidbody.velocity = movement * speed ; rigidbody.position = new Vector3 ( Mathf.Clamp (rigidbody.position.x, boundary.xMin, boundary.xMax), Mathf.Clamp (rigidbody.position.y, boundary.yMin, boundary.yMax), 0.0f ); } }

and this is the shot/bullet script :

 using UnityEngine;
 using System.Collections;
 
 public class mover : MonoBehaviour 
 {
     public float speed;
 
     void Start () 
     {
         rigidbody.velocity = transform.up * speed ;
     }
     
 
 }