Host name? Never been asked for that before.
To set up a mail account. Go to Settings > Mail, Contacts, Calendar > Add Account.
If your email account from the list. If it isn't on the list choose other.
Take for example msn,
Name = The name you want to be known as
Address = Your email address
Password = Your password for the email address you entered
Description = Add a description so you know Wichita account is which if you have more than one.
Press done when your finished and that should be you all set up...