Example:
If your email address is "joe.bloggs@teesfoyboatmen.co.uk" then enter "joe.bloggs" in the first box, and enter "teesfoyboatmen.co.uk" in the second box.
Next, enter "mail.teesfoyboatmen.co.uk" in the box labeled "Mailserver:".
Finally, enter your password in the box labeled "Password:".
Now click the button marked "Login", and you will be taken to your mailbox.