1. FTP client
First of all, please download a professional FTP program. We recommend WinSCP, a free Open Source SCP/FTP client which is probably the best one currently available. Mac users can use Cyberduck, which is also Open Source but does not have the same powerful features as WinSCP (especially when it comes to synchronizing files).
Please do not use plugins like FireFTP, because they are just plugins and not real FTP clients.