Launch Mozilla Thunderbird and follow the steps below to setup your email with IMAP.

Example:
Name: Demo
Email Address: demo@lookafter.com
Type: IMAP

Steps:

1. Go to [Tools]→ [Account Settings] and select [Add Mail Account…] under [Account Actions], OR
   directly select [Email] on “Create a new account”.
   
2. If there is a “Welcome to Thunderbird” message box popped up, select [Skip this and use my existing email]. Otherwise, skip to next step.
   
3. Enter you name on [Your name:], your email address on [Email address:], and password on [Password:]. Make sure that the [Remember password] option is selected.
   
4. Click [Continue].
5. Thunderbird will try to connect your mail server automatically. Click [Manual config] immediately.
   
6. On “Incoming”, select [IMAP], and key in your mail server mail.yourdomain.com on [Server hostname].
   Choose 143 for [Port].
   Select None for [SSL] and Normal password for [Authentication].
   
7. On “Outgoing”, key in your mail server mail.yourdomain.com on [Server hostname].
   Choose 587 for [Port].
   Select None for [SSL] and Normal password for [Authentication].
8. On “Username”, key in your full email address username@yourdomain.com on both incoming and outgoing fields.
9. Click [Done].
10. If there is warning message popped up, check [I understand the risks.] and click [Done] to finish your setup.
    

You can now access your emails using Mozilla Thunderbird.