I need some Help creating a chess game please :)

Im new to unity and C# this is my first time using them, and i want to make chess game. So far i've managed to create the board, and instantiate my chess pieces. In my game scene i have to GameObjects Board and Pieces, Board has the createBoard() fucntion that creates the board, and it calls spawnPieces() function from Pieces. the problme im having right now is making click events to move those pieces. I've seen some tuto use OnMouseDwon method but its doesn't work for me

This is the Board script :

 public GameObject[,] boardArray = new GameObject[8, 8];

 void Start()
 {
     pieces = GameObject.FindGameObjectWithTag("PiecesScript").GetComponent<PiecesScript>();

     createBoard();
     pieces.spawnPieces(boardArray);
 }

 private void createBoard()
 {
     for (int x = 0; x < 8; x++)
     {
         for (int y = 0; y < 8; y++)
         {
             if (x % 2 != 0 && y % 2 != 0 || x % 2 == 0 && y % 2 == 0)
             {
                 boardArray[x, y] = Instantiate(whiteCell, new Vector3(x * 5.11f, y * 5.11f, 0f), Quaternion.identity);
             }
             else
             {
                 boardArray[x, y] = Instantiate(blackCell, new Vector3(x * 5.11f, y * 5.11f, 0f), Quaternion.identity);
             }
         }
     }
 }

 void OnMouseDown()
 {
     Debug.Log("clicked !");
     Debug.Log(gameObject);
 }

and this is my Pieces script :

 public void spawnPieces(GameObject[,] board)
 {
     //spawning Pawns :
     for(int i = 0; i < 8; i++)
     {
         board[i, 1] = Instantiate(whitePawn, new Vector3(i * 5.11f, 1 * 5.11f, -1), Quaternion.identity);
         board[i, 6] = Instantiate(whitePawn, new Vector3(i * 5.11f, 6 * 5.11f, -1), Quaternion.identity);
     }

     //spawning Rooks :
     board[0, 0] = Instantiate(whiteRook, new Vector3(0 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[7, 0] = Instantiate(whiteRook, new Vector3(7 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[0, 7] = Instantiate(blackRook, new Vector3(0 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);
     board[7, 7] = Instantiate(blackRook, new Vector3(7 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);

     //spawning Knights :
     board[1, 0] = Instantiate(whiteKnight, new Vector3(1 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[6, 0] = Instantiate(whiteKnight, new Vector3(6 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[1, 7] = Instantiate(blackKnight, new Vector3(1 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);
     board[6, 7] = Instantiate(blackKnight, new Vector3(6 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);

     //spawning Bishops :
     board[2, 0] = Instantiate(whiteBishop, new Vector3(2 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[5, 0] = Instantiate(whiteBishop, new Vector3(5 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[2, 7] = Instantiate(blackBishop, new Vector3(2 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);
     board[5, 7] = Instantiate(blackBishop, new Vector3(5 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);

     //spawning Queens :
     board[3, 0] = Instantiate(whiteQueen, new Vector3(3 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[3, 7] = Instantiate(blackQueen, new Vector3(3 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);

     //spawning kings :
     board[4, 0] = Instantiate(whiteKing, new Vector3(4 * 5.11f, 0 * 5.11f, -1), Quaternion.identity);
     board[4, 7] = Instantiate(blackKing, new Vector3(4 * 5.11f, 7 * 5.11f, -1), Quaternion.identity);
 }
 

Thank you so much in advince :)