How and what ftp component use

If you know exact name of the file to download then you can use System.Net.WebClient class. Here is the MSDN documentation for that class: http://msdn.microsoft.com/en-us/library/system.net.webclient.aspx

If you do not know exact name of the file then you would have to use System.Net.FtpWebRequest class to list FTP directory. Here is the MSDN documentation for FtpWebRequest class: http://msdn.microsoft.com/en-us/library/system.net.ftpwebrequest.aspx

Zoran