C#

I can’t download and use official telegram api in c# to create chat program.
I need steep-by-steep tutorial to do this. And may be one little sample program in c#.

// process = new process();
process.WaitForExit(10 * 60 * 1000);
Thread.Sleep(200);
try
{
    process.Kill();
    process.WaitForExit(5000);
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}

public static void LogStatusBar(string status)
  {
       try
            {
                statusBar1.Text = "Thông báo: " + status; // error message here
            }
            catch (Exception ex)
            {

            }
  }
  private void form1_Load(object sender, EventArgs e)
   {
       ....
       LogStatusBar(Message);
       ....
   }

try
  {
     ....
  }
 catch (Exception ex)
  {
      form1.LogStatusBar(ex.Message);
  }

const int bit00 = 0x00; // 00000000
const int bit10 = 0x80; // 10000000
const int bit20 = 0xC0; // 11000000
const int bit30 = 0xE0; // 11100000
const int bit40 = 0xF0; // 11110000
const int bit50 = 0xF8; // 11111000
const int bit07 = 0x7F; // 01111111
const int bit06 = 0x3F; // 00111111
const int bit05 = 0x1F; // 00011111
const int bit04 = 0x0F; // 00001111
const int bit03 = 0x07; // 00000111

public static int ReadUTF8Char(Stream s)
{
    int c = s.ReadByte();
    if (c == -1)
    {
        return -1;
    }
    else if ((c & bit10) == bit00)
    {
        return c;
    }
    else if ((c & bit30) == bit20)
    {
        var c2 = s.ReadByte();
        return c & bit05 << 6 | c2 & bit06;
    }
    else if ((c & bit40) == bit30)
    {
        var c2 = s.ReadByte();
        var c3 = s.ReadByte();
        return c & bit04 << 12 | c2 & bit06 << 6 | c3 & bit06;
    }
    else if ((c & bit50) == bit40)
    {
        var c2 = s.ReadByte();
        var c3 = s.ReadByte();
        var c4 = s.ReadByte();
        return c & bit03 << 18 | c2 & bit06 << 12 | c3 & bit06 << 6 | c2 & bit06;
    }
    else
    {
        // what is that?
        return c;
    }
}