The File Transfer Protocol (FTP) is used to upload and download files to and from FTP servers. While you can use most modern webbrowsers (like Mozilla Firefox) to browse and download single files from FTP servers (you can click here for an example if you're using a modern browser), it is more convenient to use a dedicated FTP client to do this. You'll definitely need a FTP client to upload files or to get many files from a server. If you have a website, you'll ften need to upload your files to the webserver via FTP.
So let's get some FTP client software.
Choosing a FTP client
There are many FTP clients out there. I am using
Connecting to a server
To connect to a server, you need its DNS name (like ftp.debian.org) or IP address and a port (assume the default port 21 if no port is mentioned). If the server is non-public, you need a username and a password as well (public servers are often called 'anonymous ftp servers' and you usually are NOT allowed to upload files to these servers to prevent abuse).
Give it a try by connecting to ftp://ftp.debian.org with your FTP client:
All maps (c) by spirit