Step 1: From the Dashboard, click Settings option.
Step 2: Tap email accounts.
Step 3: From here, tap add an account option.
Step 4: Select other account from the bottom of the list.
Step 5: Enter your email address and password, then tap sign in.
Step 6: Select Internet email.
Step 7: Enter the account name (simply for your reference) you would like for this email account. Now enter your name, this is the name that will appear to other people that you send emails to.
Step 8: Under Incoming server settings, you may have to select Server type as IMAP, server address as mail.<yourdomainname.com>
Step 9: For IMAP use 143 - SSL Disabled      (If SSL enabled Use 993)
Step 10: Under Outgoing server settings, server address as mail.<yourdomainname.com>
Step 11: Outgoing SMTP port - 25 or 587 or 26 (If SSL enabled use 465)
Step 12: You will also need to check Outgoing server requires authentication and Use the same user name and password for sending email.
Finally click Sign in option.

[Note:  The incoming and outgoing mail server is an example, it is based on server]