how to compile Cosmos in C#

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C#

C#4.0

i have been making a OS in COSMOS with Visual C# 2010 Express with COSMOS Milestone 4
but, when i press F5 to debug it, i get a window that lets me select the emulator,ect then , when i click "build" on that window, it dosent build it and it starts a widow called "cosmos builder" . what am i doing wrong?
here is the code if you need it.

using System;
using Cosmos.Compiler.Builder;

namespace CosmosBoot1
{
    class Program
    {
        #region Cosmos Builder logic
        // Most users wont touch this. This will call the Cosmos Build tool
        [STAThread]
        static void Main(string[] args)
        {
            BuildUI.Run();
        }
        #endregion

        // Main entry point of the kernel
        public static void Init()
        {
            var xBoot = new Cosmos.Sys.Boot();
            xBoot.Execute();
            Console.WriteLine("Welcome! You just booted CharlieOS ! Type a command to contenue ");
            Console.ReadLine();
            if (Console.ReadLine() == ("help"))
            {
                Console.Write("Commands: 'help': displays help 'dir': makes a directory.");                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
               Console.ReadLine();  }
            else if (Console.ReadLine() == "dir")
            {
                System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(@"C:\");

                foreach (System.IO.FileInfo file in dir.GetFiles("*.*"))
                {
                    Console.WriteLine("{0}, {1}", file.Name, file.Length);
                }
                Console.ReadLine();
            }
            while (true)
                ;
            
        }
    }
}