Official unity script for shooting shots not working

I don’t know if it is because of deprecation between v.4 to 5 but following through the official unity video ‘shooting shots’: Shooting shots - 07 - Space Shooter - Unity Official Tutorials - YouTube - does not work.
Implementing the code allows the character to instantiate the shot object wherever they are, but it does not project, it just sits there.
Here is their code:

public GameObject shot;
	public Transform shotSpawn;
	public float fireRate;

	private float nextFire;

if (Input.GetButton("Fire1") && Time.time > nextFire) {
			nextFire = Time.time + fireRate;
			Instantiate(shot, shotSpawn.position, shotSpawn.rotation);

Hopefully this resource can get updated.

Attaching a script to the bullet itself did it:

        public class ShotScript : MonoBehaviour {

	public Vector2 velocity = new Vector2(5, 0);

	private Rigidbody2D shotRigid;

	void Awake()
		shotRigid = GetComponent<Rigidbody2D> ();

	void Start()
		shotRigid.velocity = velocity;
//			* transform.localScale.x