How can I add a touch screen function for android mobile game :

I have a project which is a 2d Chess game and I am making it on Mobile. Everything is working perfectly but I have this single problem which is when I try to download it on my mobile the touch screen does not work on the chess pieces. For example when I click on any chess piece it does not respond. How to fix this problem can you please tell me?

I want the touch function to use the SelectPiece() Function because I want it to be when I touch any piece I want it to select the piece and shows me where I can move it when I touch again it should move to the specific place that I chose. Basically do the same as if I am playing it on PC.

I will send you the code. I believe I should add the touch screen function in the script below because it is the one responsible for the pieces.

 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.EventSystems;
 using System.Collections.Generic;
 using System.Collections;
 using UnityEngine.Events;
 using System;
 
 public abstract class BasePiece : EventTrigger
 {
     public class MovedEvent : UnityEvent<Vector3, Vector3> { }
     public static MovedEvent Moved = new MovedEvent();
 
     [HideInInspector]
     public Color mColor = Color.clear;
     public bool mIsFirstMove = true;
 
     protected Cell mOriginalCell = null;
     protected Cell mCurrentCell = null;
 
     protected RectTransform mRectTransform = null;
     protected PieceManager mPieceManager;
 
     protected Vector3Int mMovement = Vector3Int.one;
     protected List<Cell> mHighlightedCells = new List<Cell>();
 
     public static BasePiece highlightedPiece = null;
 
     private Image image = null;
 
     private void OnEnable()
     {
         if (image)
             image.raycastTarget = true;
     }
 
     private void OnDisable()
     {
         if (image)
             image.raycastTarget = false;
     }
 
 
     public virtual void Setup(Color newTeamColor, Color32 newSpriteColor, PieceManager newPieceManager)
     {
         mPieceManager = newPieceManager;
         mColor = newTeamColor;
 
         image = GetComponent<Image>();
         image.color = newSpriteColor;
 
         mRectTransform = GetComponent<RectTransform>();
     }
 
     public virtual void Place(Cell newCell)
     {
         // Cell stuff
         mCurrentCell = newCell;
         mOriginalCell = newCell;
         mCurrentCell.mCurrentPiece = this;
 
         // Object stuff
         transform.position = newCell.transform.position;
         gameObject.SetActive(true);
     }
 
     public void Reset()
     {
         Kill();
 
         mIsFirstMove = true;
 
         Place(mOriginalCell);
     }
 
     public virtual void Kill()
     {
         // Clear current cell
         mCurrentCell.mCurrentPiece = null;
 
         // Remove piece
         gameObject.SetActive(false);
     }
 
     public bool HasMove()
     {
         CheckPathing();
 
         // If no moves
         if (mHighlightedCells.Count == 0)
             return false;
 
         // If moves available
         return true;
     }
 
     #region Movement
     private void CreateCellPath(int xDirection, int yDirection, int movement)
     {
         // Target position
         int currentX = mCurrentCell.mBoardPosition.x;
         int currentY = mCurrentCell.mBoardPosition.y;
 
         // Check each cell
         for (int i = 1; i <= movement; i++)
         {
             currentX += xDirection;
             currentY += yDirection;
 
             // Get the state of the target cell
             CellState cellState = CellState.None;
             cellState = mCurrentCell.mBoard.ValidateCell(currentX, currentY, this);
 
             // If enemy, add to list, break
             if (cellState == CellState.Enemy)
             {
                 mHighlightedCells.Add(mCurrentCell.mBoard.mAllCells[currentX, currentY]);
                 break;
             }
 
             // If the cell is not free, break
             if (cellState != CellState.Free)
                 break;
 
             // Add to list
             mHighlightedCells.Add(mCurrentCell.mBoard.mAllCells[currentX, currentY]);
         }
     }
 
     protected virtual void CheckPathing()
     {
         // Horizontal
         CreateCellPath(1, 0, mMovement.x);
         CreateCellPath(-1, 0, mMovement.x);
 
         // Vertical 
         CreateCellPath(0, 1, mMovement.y);
         CreateCellPath(0, -1, mMovement.y);
 
         // Upper diagonal
         CreateCellPath(1, 1, mMovement.z);
         CreateCellPath(-1, 1, mMovement.z);
 
         // Lower diagonal
         CreateCellPath(-1, -1, mMovement.z);
         CreateCellPath(1, -1, mMovement.z);
     }
 
     protected void ShowCells()
     {
         foreach (Cell cell in mHighlightedCells)
             cell.mOutlineImage.enabled = true;
     }
 
     protected void ClearCells()
     {
         foreach (Cell cell in mHighlightedCells)
             cell.mOutlineImage.enabled = false;
 
         mHighlightedCells.Clear();
     }
 
     public virtual void MoveTo(Cell cell)
     {
         // Log
         print(gameObject.name + mCurrentCell.name + " > " + cell.name);
 
         // Hide
         ClearCells();
 
         // First move switch
         mIsFirstMove = false;
 
         // If there is an enemy piece, remove it
         cell.RemovePiece();
 
         // Clear current
         mCurrentCell.mCurrentPiece = null;
 
         // Move Event
         Moved.Invoke(transform.position, cell.transform.position);
 
         // Switch cells
         mCurrentCell = cell;
         mCurrentCell.mCurrentPiece = this;
 
         // Move on board
         transform.position = mCurrentCell.transform.position;
         highlightedPiece = null;
 
         // End turn
         mPieceManager.SwitchSides(mColor);
 
         SoundManager.PlaySound();
     }
     #endregion
 
     #region Events
 
 #if UNITY_EDITOR
     public override void OnPointerClick(PointerEventData eventData)
     {
         base.OnPointerClick(eventData);
         SelectPiece();
     }
 #endif
 
     public void SelectPiece()
     {
         if (highlightedPiece == this)
         {
             highlightedPiece.ClearCells();
             highlightedPiece = null;
             return;
         }
 
         if (highlightedPiece)
         {
             highlightedPiece.ClearCells();
         }
 
         highlightedPiece = this;
 
         // Test for cells
         CheckPathing();
 
         // Show valid cells
         ShowCells();
     }
 
     #endregion
 }
 
 

Thank you for reading my question and either way I will keep searching on the internet hopefully I can find something helpful. Any help would be appreciated.