Top Down Shooter - controller.move error cs0117

Hi, I am begging to code for a top down shooter and I can't seem to get the .move working. (Shows in redtext) If I look at tutorials or videos guiding me through it seems to work everytime for them.

 using UnityEngine;
 using System.Collections;
 
 public class CharacterController : MonoBehaviour {
     
     // Variables
     private CharacterController characterController;
     private Quaternion targetRotation;
     
     //Movement Variables
     public float walkSpeed = 4;
     public float rotateSpeed = 380;
     public float runSpeed = 9;
     
     // Use this for initialization
     void Start () {
         //NTS - Never put a getcomponent task in the update method as it's too slow. (ends up loading every frame)
         characterController = GetComponent<CharacterController> ();
         
     }
     
     // Update is called once per frame
     void Update () {
         
         // Gets the player input for control
         Vector3 playerInput = new Vector3 (Input.GetAxisRaw ("Horizontal"),0, Input.GetAxisRaw ("Vertical"));
         
         if (playerInput != Vector3.zero) {
             targetRotation = Quaternion.LookRotation(playerInput);
             transform.eulerAngles = Vector3.up * Mathf.MoveTowardsAngle (transform.eulerAngles.y,
                                                                          targetRotation.eulerAngles.y,
                                                                          rotateSpeed * Time.deltaTime);
         }
 
         Vector3 playerMotion = playerInput;
         //adds gravity
         playerMotion += Vector3.up * -8;
         CharacterController.characterController.Move(playerMotion * Time.deltaTime);
         
     }
 
 }