this is an example, to setup a working ftp server

offcourse connect your USB-HDD or USB-Stick to the WL500g

apply the changes to your router and finish

after that you should be able to login with ftp://test:test@my.router:21

e.g.

username: test
password: test
host: my.router
port:21

you can use www.flashfxp.com as FTP program