If you don't have a Nb mail address. you can create an email id from here then you can Nb email login.
Open Thunderbird Software App. Click on Email
When you click on the email, pop-up Set UP an Existing Account Screen.
Enter Your name, Nb Email address and Password then press Continue.
Click on the Manual config menu at bottom.
Enter Below Nb incoming server settings.
In incoming click on the dropdown menu and select POP.
Add server host :pop.bellaliant.net
Port: 110
select SSL/TLS
Enter Below Nb outgoing server settings.
In outgoing select SMTP.
Add server host :smtpa.bellaliant.net
Port: 2225
select SSL/TLS
Tap on Done. Now you are ready to use your Nb email account on your Thunderbird.