How to Work With Delegate and Event

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class _Default : System.Web.UI.Page 
{   
    public delegate  void delFirst(int i);
    public event  delFirst evenFirts;
 
    protected void Page_Load(object sender, EventArgs e)
    {
        Button bt = new Button();
        bt.Attributes.Add("runat", "server");
        bt.Text = "EVENT";

        bt.Click += new EventHandler(eventTest);
        form1.Controls.Add(bt);

        delFirst delF;
        delF = Add;
        delF += sub;

        evenFirts = delF;//new delFirst(Add);
        //evenFirts += delF;//new delFirst(sub);

    }
    public void eventTest(object sender, EventArgs e)
    {
        Button bt1 = (Button)sender;
        bt1.Text = "Clicked";
        evenFirts(5);

    }
   
        public void Add(int i)
        {
            Label1.Text += "From Add :" + i;
        
             
        }
        public void sub(int i)
        {
            Label1.Text += "From Sub :" + i;
        }
     
}