Trying to make sliding doors. With transform, but it jumps to position. What am I doing wrong?

Hello.

Like my subject says. I am no coder, still learning. Trying to make sliding doors, but at the moment, it just jumps between the cordinates i have set. I want it to move smoothly to position, can anyone give me a hand with this? I have tried to read documentation, and searched around on google, without any luck.

Thanks in advance. (Let me know if you need any more info);

 public class SliderDoor : MonoBehaviour {
 
     [Header("Speed and new position")]
     public float SlideSpeed = 1.0f;
     public float moveSpeed; // FOR TESTING, CHANGE TO PRIVATE - Value changes from 0.0.007408588 to 0.0165667 - is this right?
     public Vector3 MoveTo;
 
     [Space(15)]
     [Header("GUI Text")]
     public string OpenText = "Click E to open door";
     public string CloseText = "Click E to close door";
 
     // PRIVATE VARIABLES
     // VECTOR 3
     private Vector3 OldPosition;
     // BOOL
     private bool _isInsideTrigger = false;
     private bool isDoorOpen = false;
     
 
     void Start()
     {
         OldPosition = transform.localPosition;
     }
 
     void OnTriggerEnter(Collider other)
     {
         if (other.tag == "Player")
         {
             _isInsideTrigger = true;
             Debug.Log("PLAYER IS INSIDE TRIGGER AREA - _isInsideTrigger = " + _isInsideTrigger);
 
         }
     }
 
     void OnTriggerExit(Collider other)
     {
         if (other.tag == "Player")
         {
             _isInsideTrigger = false;
             Debug.Log("PLAYER EXITED TRIGGER AREA - _isInsideTrigger = " + _isInsideTrigger);
 
         }
     }
 
 
     void Update()
     {
         moveSpeed = SlideSpeed * Time.deltaTime; // CAN I SET THIS IN START? - Test when door is sliding
 
         if (!isDoorOpen && _isInsideTrigger)
         {
     
             if (Input.GetKeyDown(KeyCode.E))
             {
                 SlideDoorOpen();
           }
         }
         else if (isDoorOpen && _isInsideTrigger)
         {
             if (Input.GetKeyDown(KeyCode.E))
             {
                 SlideDoorClose();
             }
         }
     }
 
     void SlideDoorOpen()
     {
         isDoorOpen = true;
         transform.localPosition = Vector3.MoveTowards(OldPosition, MoveTo, moveSpeed);
     }
 
     void SlideDoorClose()
     {
         isDoorOpen = false;
         transform.localPosition = Vector3.MoveTowards(MoveTo, OldPosition, moveSpeed);
     }
 
     void OnGUI()
     {
         if (_isInsideTrigger && !isDoorOpen)
         {
             GUI.BeginGroup(new Rect(Screen.width / 2 - 200, 100, 450, 420));
             GUI.Box(new Rect(0, 0, 330, 80), "");
 
             GUI.Label(new Rect(15, 30, 400, 23), OpenText);
             GUI.EndGroup();
         }
 
         else if (_isInsideTrigger && isDoorOpen)
         {
             GUI.BeginGroup(new Rect(Screen.width / 2 - 200, 100, 450, 420));
             GUI.Box(new Rect(0, 0, 330, 80), "");
 
             GUI.Label(new Rect(15, 30, 400, 23), CloseText);
             GUI.EndGroup();
         }
     }
 }