With Fiery's you need to setup an email account on the actual email server as if the device is a new employee. They can work via Exchange and web based email.
Once you have set the email account up on the server, navigate via Internet Explorer to the ip address of the device.
You should find a Fiery Tools button somewhere on the left once the page loads.
Click fiery tools and setup all the normal POP3 stuff.
Oh, just in case you don't know, and assuming the Fiery password hasn't been changed, it's Fiery.1
Where you're done, power down the Fiery and then reboot.
Good luck