How to Setting up Mail in Thunderbird on your Mac/Apple or Windows.
Select >Tools > Account Settings

1. Click Add Account
2. Select Email Account and click Next
Your Name: [Your Full Name]
Email Address: [email@domain.com]

IMAP Instructions:
Incoming Server: [hostname.server.com]
Outgoing Server: [hostname.server.com]
If you know mail.domain.com is set up to point to the proper location, you may use that in place of hostname.server.com.

POP3 Instructions:
Incoming Server: [hostname.server.com]
Outgoing Server: [hostname.server.com]
If you know mail.domain.com is set up to point to the proper location, you may use that in place of hostname.server.com.

Verify your information and Click Done
