On a Windows PC, a popular free (trial) FTP program is WS_FTP. You may find it here.
As well, a tutorial on how to use WS_FTP can be found here.
Please note that the default FTP account created (note that certain plans allow only the default FTP account) uses Username: email@example.com (e.g. Username: firstname.lastname@example.org), which is unlike most traditional control panels. The password is set through Siteworx, under the FTP section, and can be changed very easily.