Trying to write a chat program using WCF, but I have no idea how

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.ServiceModel;

namespace WinChatForm
{
    [ServiceContract]
    interface IQuickP2PChat
    {
        [OperationContract(IsOneWay = true)]
        void Join(string nickname);
        [OperationContract(IsOneWay = true)]
        void SendMessage(string nickname, string msgbox);
        [OperationContract(IsOneWay = true)]
        void Leave(string nickname);
    }
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
    public partial class Main : Form, IQuickP2PChat
    {
        ServiceHost _host;
        IQuickP2PChat _proxy;
        string _nickname;
        ChannelFactory<IQuickP2PChat> factory;
        public Main()
        {
            InitializeComponent();
        }

        private void InitHost()
        {
            _host = new ServiceHost(this);
            _host.Open();
            //통신을 위한 클라이언트 프록시 구성
            factory = new ChannelFactory<IQuickP2PChat>("QuickP2PChatEndpoint");
            _proxy = factory.CreateChannel();
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (_proxy != null)
            {
                factory.Close();
            }
            if (_host != null && _host.State != CommunicationState.Closed)
            {
                _host.Close();
            }
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (textBox1.Text == "")
            {
                button1.Enabled = false;
            }
            else
            {
                button1.Enabled = true;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            InitHost();
            //채팅에 사용할 이름을 입력받는다.
            _nickname = textBox1.Text;
            _proxy.Join(_nickname);
            panel1.Enabled = true;
            textBox1.Text = "";
            textBox1.Enabled = false;
        }

        private void btnInputMsg_Click(object sender, EventArgs e)
        {
            string temp = txtInputMsg.Text + Environment.NewLine;
            _proxy.SendMessage(_nickname,temp);
            txtInputMsg.Clear();
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            _proxy.Leave(_nickname);
            this.Close();
        }

        void IQuickP2PChat.Join(string nickname)
        {
            txtShow.Text  += nickname + "Joined!!" + Environment.NewLine;
            lstUser.Items.Add(nickname);
        }

        void IQuickP2PChat.SendMessage(string nickname, string msgbox)
        {
            txtShow.Text = "[" + nickname + "]" + " " + msgbox;
        }

        void IQuickP2PChat.Leave(string nickname)
        {
            txtShow.Text = nickname + "Leaved!!" + Environment.NewLine;
            lstUser.Items.Remove(nickname);
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <bindings>
      <netPeerTcpBinding>
        <binding  name="BindingUnsecure">
          <security mode="None"/>
          <resolver mode="Pnrp"/>
        </binding>
      </netPeerTcpBinding>
    </bindings>
    <services>
      <service name="WinChatForm.Main">
        <host>
          <baseAddresses>
            <add baseAddress="net.p2p://QuickP2PChat"/>
          </baseAddresses>
        </host>
        <endpoint
            contract="WinChatForm.IQuickP2PChat"
            address=""
            binding="netPeerTcpBinding"
            bindingConfiguration="BindingUnsecure"
          />
      </service>
    </services>
    <client>
      <endpoint
          name="QuickP2PChatEndpoint"
          address="net.p2p://QuickP2PChatChat"
          binding="netPeerTcpBinding"
          bindingConfiguration="BindingUnsecure"
          contract="WinChatForm.IQuickP2PChat"
      />
    </client>
  </system.serviceModel>
</configuration>