You need to know your login name (username), your ftp password, and the url of the ftp server. You should have been provided with these already by your web host. If not, contact them.
I don't know much about FileZilla, but you should be able to use it to connect to the ftp server provided by your web host. Most ftp clients use some sort of 2 panel format, with your local files on one side, and the remote files on the other.
Visit the filezilla wiki for more help!