Character Movement not moving how i want

Hi there and thanks for looking. I have some code right now that kinda works how i want. I want it to strafe left and right go back and forth. Things is when i press W he will always go forward no matter where my camera is facing. I want it to be where he fill go in the direction my camera is facing.

I am trying to get this controller to be like Ratchet And Clanks character controller so any help on how to do this or just help me with the above would be amazing.

I am trying to learn movements as they confuse the shizzle out of me. I do understand code very well but when it comes to this kinda thing it just goes over my head so any help with this would also be amazing.

Here is the code

 using UnityEngine;
 using System.Collections;
 
 public class PlayerController : MonoBehaviour {
 
     private CharacterController controller;
     private Vector3 moveDirection;
     private Vector3 forward;
     private Vector3 right;
     public float speed;
     // Use this for initialization
     void Start () {
 
         controller = gameObject.GetComponent<CharacterController>();
         moveDirection = Vector3.zero;
         right = Vector3.zero;
         forward = Vector3.zero;
     }
     
     // Update is called once per frame
     void Update () {
         // anhance this but leanr more as you go forward. Learn each statement so you know what it is 
         forward = Vector3.forward;
         right = new Vector3(forward.z, 0, -forward.x);
         float horizontalInput = Input.GetAxisRaw("Horizontal");
         float verticalInput = Input.GetAxisRaw("Vertical");
 
         Vector3 targetDirection = horizontalInput * right + verticalInput * forward;
         moveDirection = Vector3.RotateTowards(moveDirection, targetDirection, 200 * Mathf.Deg2Rad * Time.deltaTime, 1000);
 
         Vector3 movement = moveDirection * Time.deltaTime * speed ;
         controller.Move(movement);
         Mathf.Clamp(0,0,0);
         float lookRot = Input.mousePosition.z;
         if (targetDirection != Vector3.zero)
         {
             
             Vector3 relativePos = transform.position - Camera.main.transform.position;
             float x, y, z;
             x = relativePos.x;
             y = 0;
             z = relativePos.z;
             Vector3 look = new Vector3(x, y, z);
             Quaternion rotation = Quaternion.LookRotation(look * Time.deltaTime * 2);
 
             transform.rotation = rotation;
         }
     }
 }