How to highlight a selected inventory slot.

Hey, Im new to learning C#. I have been following a tutorial on YouTube about an inventory system. However, I want to highlight a selected inventory slot without highlighting the remaining slots. I can't seem to figure out how to do this. Sorry if this is a beginner problem.

 public MouseItem mouseItem = new MouseItem();
 public GameObject inventoryPrefab;
 public InventoryObject inventory;
 public int X_START;
 public int Y_START;
 public int X_SPACE_BETWEEN_ITEMS;
 public int NUMBER_OF_COLUMN;
 public int Y_SPACE_BETWEEN_ITEMS;
 public bool hover = false;
  

 Dictionary<GameObject, InventorySlot> itemsDisplayed = new Dictionary<GameObject, InventorySlot>();
 // Start is called before the first frame update
 void Start()
 {
     CreateSlots();
 }

 // Update is called once per frame
 void Update()
 {
     UpdateSlots();
 }

  public void UpdateSlots()
 {
     foreach (KeyValuePair<GameObject, InventorySlot> _slot in itemsDisplayed)
     {
         if (_slot.Value.ID >= 0)
         {
             _slot.Key.transform.GetChild(0).GetComponentInChildren<Image>().sprite = inventory.database.GetItem[_slot.Value.item.Id].uiDisplay;
             _slot.Key.transform.GetChild(0).GetComponentInChildren<Image>().color = new Color(1, 1, 1, 1);
             _slot.Key.GetComponentInChildren<TextMeshProUGUI>().text = _slot.Value.amount == 1 ? "" : _slot.Value.amount.ToString("n0");
         }
         else
         {
             _slot.Key.transform.GetChild(0).GetComponentInChildren<Image>().sprite = null;
             _slot.Key.transform.GetChild(0).GetComponentInChildren<Image>().color = new Color(1, 1, 1, 0);
             _slot.Key.GetComponentInChildren<TextMeshProUGUI>().text = "";
         }
     }
 }

 public void CreateSlots()
 {
     itemsDisplayed = new Dictionary<GameObject, InventorySlot>();
     for (int i = 0; i < inventory.Container.Items.Length; i++)
     {
         var obj = Instantiate(inventoryPrefab, Vector3.zero, Quaternion.identity, transform);
         obj.GetComponent<RectTransform>().localPosition = GetPosition(i);
 
         
         AddEvent(obj, EventTriggerType.PointerEnter, delegate { OnEnter(obj); });
         AddEvent(obj, EventTriggerType.PointerExit, delegate { OnExit(obj); } );
         AddEvent(obj, EventTriggerType.BeginDrag, delegate { OnDragStart(obj); } );
         AddEvent(obj, EventTriggerType.EndDrag, delegate { OnDragEnd(obj); } );
         AddEvent(obj, EventTriggerType.Drag, delegate { OnDrag(obj); } );


         itemsDisplayed.Add(obj, inventory.Container.Items[i]);
     }
     
 }

 private void AddEvent(GameObject obj, EventTriggerType type, UnityAction<BaseEventData> action)
 {
     EventTrigger trigger = obj.GetComponent<EventTrigger>();
     var eventTrigger = new EventTrigger.Entry();
     eventTrigger.eventID = type;
     eventTrigger.callback.AddListener(action);
     trigger.triggers.Add(eventTrigger);
 }

 private void OnTriggerEnter(Collider other)
 {
     GetComponent<Image>().color = new Color(0.2924528f, 1, 0.2924528f, 1);
                   
 }

 public void OnEnter(GameObject obj)
 {
     mouseItem.hoverObj = obj;
     if(itemsDisplayed.ContainsKey(obj))
     {
         mouseItem.hoverItem = itemsDisplayed[obj];
         hover = true;
     }

 }

 public void OnExit(GameObject obj)
 {
     mouseItem.hoverObj = null;
     mouseItem.hoverItem = null;
     hover = false;      
 }

 public void OnDragStart(GameObject obj)
 {
     var mouseObject = new GameObject();
     var rt = mouseObject.AddComponent<RectTransform>();
     rt.sizeDelta = new Vector2(100, 100);
     mouseObject.transform.SetParent(transform.parent);
     if(itemsDisplayed[obj].ID >= 0)
     {
         var img = mouseObject.AddComponent<Image>();
         img.sprite = inventory.database.GetItem[itemsDisplayed[obj].ID].uiDisplay;
         img.raycastTarget = false;
         hover = true;
     }
     mouseItem.obj = mouseObject;
     mouseItem.item = itemsDisplayed[obj];
 }

 public void OnDragEnd(GameObject obj)
 {
     if (mouseItem.hoverObj)
     {
         inventory.MoveItem(itemsDisplayed[obj], itemsDisplayed[mouseItem.hoverObj]);
     }
     else
     {
         inventory.RemoveItem(itemsDisplayed[obj].item);
     }
     Destroy(mouseItem.obj);
     mouseItem.item = null;
     hover = false;

 }

 public void OnDrag(GameObject obj)
 {
     if(mouseItem.obj != null)
     {
         hover = true;
         mouseItem.obj.GetComponent<RectTransform>().position = Input.mousePosition;
     }
         
 }
 
 public Vector3 GetPosition(int i)
 {
     return new Vector3(X_START + (X_SPACE_BETWEEN_ITEMS *(i % NUMBER_OF_COLUMN)), Y_START + (-Y_SPACE_BETWEEN_ITEMS * (i/NUMBER_OF_COLUMN)), 0f);
 }
 

}

public class MouseItem { public GameObject obj; public InventorySlot item; public InventorySlot hoverItem; public GameObject hoverObj; }