Click tools, account settings: (press ALT on your keyboard if Tools is not visible).
Select Add Mail Account.
Type in your full name, email address and case sensitive password.
Select IMAP, and the Manual Config.
Your incoming IMAP mailserver is mail.yourdomainname.com - Port 143 - STARTTLS - Encrypted password.
Your outgoing STMP mailserver is mail.yourdomainname.com - Port 25 - STARTTLS - Encrypted password.
Your username is your FULL email address.
Once complete, press done.
You will be prompted with a certificate warning - Click Confirm Security Exception.
You will now be back at the account settings menu - under Server Settings click Advanced.
In the "IMAP server directory" type INBOX.
Press OK again.