I want to move my gameobject on z axis. I have a problem with my script. Please help! C#

Hello everyone.. I have a drawer script.. Actually it was door script. I tried to change it for open/close drawer. I use this script with another Interact script (i'ts working i tried) . This is my script:

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class Drawer : MonoBehaviour {
 
     public bool open = false;
 
     public float speed = 2f;
 
     private AudioSource audioSource;
     public AudioClip openingSound;
     public AudioClip lockedDrawerSound;
 
     public bool isLocked = false;
 
     public GameObject lockedText;
     public float textTime = 4f;
     public Transform target;
 
 
     void Start()
     {
         audioSource = GetComponent<AudioSource> ();
         lockedText.SetActive (false);
 
     }
 
     public void ChangeDrawerState()
     {
         if (isLocked != true) {
             open = !open;
 
             if (audioSource != null) {
                 audioSource.PlayOneShot (openingSound);
             }
         }
         else
         {
             StartCoroutine(LockedDrawer());
             lockedText.SetActive (true);
         }
 
     }
 
     IEnumerator LockedDrawer()
     {
         audioSource.PlayOneShot (lockedDrawerSound);
         yield return new WaitForSeconds (textTime);
         lockedText.SetActive (false);
 
     }
 
     void Update ()
     {
         if(open)
         {
             float step = speed * Time.deltaTime;
             transform.position = Vector3.MoveTowards(transform.position, target.position, step);
         }
         else
         {
             float step = speed * Time.deltaTime;
             target.position = Vector3.MoveTowards(target.position, transform.position, step);
         }
     }
 }

there is no error but it's not opening or closing drawer too... What should i do? What is wrong in this script? i am not good at this "Vector3" and "transform" things.. Please help me :) Thanks