this is generally where you either have a crisis of faith and decide linux isn't for you or you go out and find a howto on installing an ftp server.
things you need for an ftp server to work..
the ftp server itself (look at vsftpd, pure-ftpd or wuftpd)
a working network card.
proabably missed something but these are the main ones
- may come in handy as well. theres a whole host of howtos and whatnot.
have a crack at installing one of the ftp servers above and come back if you have any problems