CODE (BallMovement):
using System.Collections;  using System.Collections.Generic;  using UnityEngine;   public class BallMovement : MonoBehaviour {  public float speed = 25.0F;  public float jumpSpeed = 8.0F;   public float gravity = 20.0F;  private Vector3 moveDirection = Vector3.zero;  private float turner;  private float looker;  public float sensitivity = 5;    // Use this for initialization  void Start () {    }    // Update is called once per frame  void Update () {  CharacterController controller = GetComponent<CharacterController>();   // is the controller on the ground?  if (controller.isGrounded) {  //Feed moveDirection with input.  moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));  moveDirection = transform.TransformDirection(moveDirection);  //Multiply it by speed.  moveDirection *= speed;  //Jumping  if (Input.GetButton("Jump"))  moveDirection.y = jumpSpeed;    }  turner = Input.GetAxis ("Mouse X")* sensitivity;  looker = -Input.GetAxis ("Mouse Y")* sensitivity;  if(turner != 0){  //Code for action on mouse moving right  transform.eulerAngles += new Vector3 (0,turner,0);  }  if(looker != 0){  //Code for action on mouse moving right  transform.eulerAngles += new Vector3 (looker,0,0);  }  //Applying gravity to the controller  moveDirection.y -= gravity * Time.deltaTime;  //Making the character move  controller.Move(moveDirection * Time.deltaTime);  }  } ////////////////////////////////////////////////////////////////
CODE (FollowPlayer):
using System.Collections; using System.Collections.Generic; using UnityEngine;  public class FollowPlayer : MonoBehaviour {  public GameObject player;  public float EnemeySpeed = 4f;    // Start is called before the first frame update  void Start()  {    }   // Update is called once per frame  void Update()  {  transform.LookAt(player.transform);  transform.position += transform.forward * EnemeySpeed * Time.deltaTime;  } } ////////////////////////////////////////////////////////////////
CODE (Gun):  
using System.Collections; using System.Collections.Generic; using UnityEngine;   public class Gun : MonoBehaviour {  public Transform bulletSpawnPoint;  public GameObject bulletPrefab;  public float bulletSpeed = 10;    void Update()  {  if(Input.GetKeyDown(KeyCode.X))  {  var bullet = Instantiate(bulletPrefab, bulletSpawnPoint.position, bulletSpawnPoint.rotation);  bullet.GetComponent<Rigidbody>().velocity = bulletSpawnPoint.forward * bulletSpeed;  }  } }