Where to add subscription

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        Account MyAccount = new Account(10000);
        subscriber Mysubscriber = new subscriber();

        public Form1()
        {
            InitializeComponent();
            MyAccount.TransactionMade += new TransactionHandler(Mysubscriber.SendNotification);
        }

       
        private void ButtonCredit(object sender, EventArgs e)
        {
            MyAccount.Credit(500);
            MessageBox.Show("your current balance is ", MyAccount.BalanceAmount.ToString());
        }
    }
}

namespace WindowsFormsApp1
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }


    public delegate void TransactionHandler(object sender, TransactionEventArgs e); // Delegate Definition
    class Account
    {
        public event TransactionHandler TransactionMade; // Event Definition

        public int BalanceAmount;

        public Account(int amount)
        {
            this.BalanceAmount = amount;

        }

        public void Debit(int debitAmount)
        {
            if (debitAmount < BalanceAmount)
            {
                BalanceAmount = BalanceAmount - debitAmount;
                TransactionEventArgs e = new TransactionEventArgs(debitAmount, "Debited");
                OnTransactionMade(e); // Debit transaction made
            }
        }

        public void Credit(int creditAmount)
        {

            BalanceAmount = BalanceAmount + creditAmount;
            TransactionEventArgs e = new TransactionEventArgs(creditAmount, "Credited");
            OnTransactionMade(e); // Credit transaction made

        }

        protected virtual void OnTransactionMade(TransactionEventArgs e)
        {
            if (TransactionMade != null)
            {
                TransactionMade(this, e); // Raise the event 
            }
        }

    }


    public class TransactionEventArgs : EventArgs
    {
        public int TranactionAmount { get; set; }
        public string TranactionType { get; set; }

        public TransactionEventArgs(int amt, string type)
        {
            TranactionAmount = amt;
            TranactionType = type;
        }
    }


    public class subscriber
    {

        public void SendNotification(object sender, TransactionEventArgs e)
        {
            //Console.WriteLine("Your Account is {0} for Rs.{1} ", e.TranactionType, e.TranactionAmount);
            MessageBox.Show(e.TranactionType);
            MessageBox.Show(e.TranactionAmount.ToString());
        }



    }
}