What code should I change to make this multiplayer checkers game be com vs com ?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CheckerBoard : MonoBehaviour {
    
    public Piece[,] pieces = new Piece[8, 8];
    public GameObject whitePiece;
    public GameObject blackPiece;

    private Vector3 boardoffset = new Vector3(-4.0f, 0, -4.0f);
    private Vector3 pieceoffset = new Vector3(0.5f, 0, 0.5f);

    private Piece SelectedPiece;
    private List<piece> forcedPieces; 

    public bool isWhite;
    private bool isWhiteTurn;
    private bool hasKilled;


    private Vector2 mouseover;
    private Vector2 startDrag;
    private Vector2 endDrag;
    

    private void Start()
    {
        isWhiteTurn = true;
        isWhite = true;
        forcedPieces = new List<piece>();
        GenerateBoard();
    }

    private void Update()
    {
        UpdateMouseOver();

        //if it is my turn
        if((isWhite)?isWhiteTurn:!isWhiteTurn)
        {
            int x = (int)mouseover.x;
            int y = (int)mouseover.y;

            if (SelectedPiece != null)
            {
                UpdatePieceDrag(SelectedPiece);
            }
            if (Input.GetMouseButtonDown(0))
            {
                SelectPiece(x, y);
            }

            if (Input.GetMouseButtonUp(0))
                TryMove((int)startDrag.x, (int)startDrag.y, x, y);
        }
        
    }

    private void UpdateMouseOver()
    {
        //if it is my turn
        if(!Camera.main)
        {
            Debug.Log("Unable to find main camera");
            return;
        }
        RaycastHit hit;
        if(Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition),out hit,25.0f,LayerMask.GetMask("Board")))
        {
            mouseover.x = (int)(hit.point.x - boardoffset.x);
            mouseover.y = (int)(hit.point.z - boardoffset.z);
        }
        else
        {
            mouseover.x = -1;
            mouseover.y = -1;
        }
    }

    private void GenerateBoard()
    {
        // generate white pieces
        for(int y=0; y<3; y++)
        {
            bool oddRow = (y % 2 == 0);
            for(int x=0; x<8; x+=2)
            {
                //generate our pieces
                GeneratePiece((oddRow) ? x : x +1, y);
            }
        }

        //generate black pieces
        for (int y = 7; y > 4; y--)
        {
            bool oddRow = (y % 2 == 0);
            for (int x = 0; x < 8; x += 2)
            {
                //generate thier pieces
                GeneratePiece((oddRow) ? x : x + 1, y);
            }
        }
    }

    private void GeneratePiece(int x, int y)
    {
        bool isPieceWhite = (y > 3) ? false : true;
        GameObject go = Instantiate(isPieceWhite?whitePiece:blackPiece) as GameObject;
        go.transform.SetParent(transform);
        Piece p = go.GetComponent<piece>();
        pieces[x, y] = p;
        MovePiece(p, x, y);
    }

    private void MovePiece(Piece p, int x, int y)
    {
        p.transform.position = (Vector3.right * x) + (Vector3.forward * y) + boardoffset + pieceoffset;
    }

    private void SelectPiece(int x, int y)
    {
        //Out of bound
        if (x < 0 || x >= 8 || y < 0 || y >= 8)
            return;
        Piece p = pieces[x, y];
        if(p != null && p.isWhite == isWhite)
        {
            if (forcedPieces.Count == 0)
            {
                SelectedPiece = p;
                startDrag = mouseover;
            }

            else
            {
                //look for the piece under our forced pieces list
                if (forcedPieces.Find(fp => fp == p) == null)
                    return;

                SelectedPiece = p;
                startDrag = mouseover;
            }
        }
    }

    private void TryMove(int x1,int y1,int x2,int y2)
    {

        forcedPieces = ScanForPossibleMove();

        //Multiplayer Support
        startDrag = new Vector2(x1, y1);
        endDrag = new Vector2(x2, y2);
        SelectedPiece = pieces[x1, y1];

        //error
        if(x2 < 0 || x2 >= 8 || y2 < 0 || y2 >= 8)
        {
            if (SelectedPiece != null)
            {
                MovePiece(SelectedPiece, x1,y1);
            }
            startDrag = Vector2.zero;
            SelectedPiece = null;
            return;
        }

        if(SelectedPiece != null)
        {
            //if it has not moved
            if( endDrag == startDrag)
            {
                MovePiece(SelectedPiece, x1, y1);
                startDrag = Vector2.zero;
                SelectedPiece = null;
                return;
            }
            //check if its a valid move
            if(SelectedPiece.validMove(pieces, x1, y1, x2, y2))
            {
                //did we kill anything
                //if this is a jump
                if(Mathf.Abs(x2 - x1) == 2)
                {
                    Piece p = pieces[(x1 + x2) / 2, (y1 + y2) / 2];
                    if(p != null)
                    {
                        pieces[(x1 + x2) / 2, (y1 + y2) / 2] = null;
                        Destroy(p.gameObject);
                        hasKilled = true;
                    }
                }

                //we are supposed to killaa anything?

                if(forcedPieces.Count != 0 && !hasKilled)
                {
                    MovePiece(SelectedPiece, x1, y1);
                    startDrag = Vector2.zero;
                    SelectedPiece = null;
                    return;
                }

                pieces[x2, y2] = SelectedPiece;
                pieces[x1, y1] = null;
                MovePiece(SelectedPiece,x2, y2);
                EndTurn();
            }
            else
            {
                MovePiece(SelectedPiece, x1, y1);
                startDrag = Vector2.zero;
                SelectedPiece = null;
                return;
            }
        }
 }

    private void EndTurn()
    {
        int x = (int)endDrag.x;
        int y = (int)endDrag.y;

        //promotions
        if(SelectedPiece != null)
        {
            if(SelectedPiece.isWhite && !SelectedPiece.isKing && y == 7)
            {
                SelectedPiece.isKing = true;
                SelectedPiece.transform.Rotate(Vector3.right * 180);
            }

            else if(!SelectedPiece.isWhite && !SelectedPiece.isKing && y == 0)
            {
                SelectedPiece.isKing = true;
                SelectedPiece.transform.Rotate(Vector3.right * 180);
            }
             
        }
        SelectedPiece = null;
        startDrag = Vector2.zero;

        if (ScanForPossibleMove(SelectedPiece, x, y).Count != 0 && hasKilled)
            return;


        isWhiteTurn = !isWhiteTurn;
        isWhite = !isWhite;
        hasKilled = false;
        CheckVictory();
    }

    private void CheckVictory()
    {
        var ps = FindObjectsOfType<piece>();
        bool hasWhite = false, hasBlack = false;
        for(int i = 0; i < ps.Length; i++)
        {
            if (ps[i].isWhite)
                hasWhite = true;
            else
                hasBlack = true;

        }

        if (!hasWhite)
            Victory(false);
        if (!hasBlack)
            Victory(true);
    }

    public void Victory(bool isWhite)
    {
        if (isWhite)
            Debug.Log("White player has won");
        else
            Debug.Log("Black player has won");

    }

    private List<piece> ScanForPossibleMove()
    {
        forcedPieces = new List<piece>();

        //check all the pieces
        for (int i = 0; i < 8; i++)
            for (int j = 0; j < 8; j++)
                if (pieces[i, j] != null && pieces[i, j].isWhite == isWhiteTurn)
                    if (pieces[i, j].IsForceToMove(pieces, i, j))
                        forcedPieces.Add(pieces[i, j]);
        return forcedPieces;
    }

    private List<piece> ScanForPossibleMove(Piece p, int x, int y)
    {
        forcedPieces = new List<piece>();

        if (pieces[x, y].IsForceToMove(pieces, x, y))
            forcedPieces.Add(pieces[x, y]);

        return forcedPieces;
    }

    private void UpdatePieceDrag(Piece p)
    {
        //if it is my turn
        if (!Camera.main)
        {
            Debug.Log("Unable to find main camera");
            return;
        }
        RaycastHit hit;
        if (Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), out hit, 25.0f, LayerMask.GetMask("Board")))
        {
            p.transform.position = hit.point + Vector3.up;
        }
    }

}