Write a .Net Class to Modify a message in Pipeline from Business Rule Engine

Question

I have a requirement where i have to modify the incoming message in Receive pipeline which i want to do using BRE Pipleline , I have written the Code in a console Application for Testing purpose but how to write a separate assembly and use in BRE Vocabulary , I know how to use the BRE Pipeline to call the Polict but need help with .net assemble , Below is the code which i wrote and working 

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)


        {

            String sourceDirectory = @"C:\Console\New folder\In.txt";
            String targetDirectory = @"C:\Console\New folder\Out.txt";


            var all = File.ReadAllLines(sourceDirectory).ToList();
            var dataLines = all.Where(l => Regex.IsMatch(l, @"^\d+"));
            var lines = all.Take(2).Concat(dataLines).ToList();
            File.WriteAllLines(targetDirectory, lines);



        }
    }
}

Appreciate the help 

---

Sukra