This documentation is geared towards Thunderbird and it will also assume that you have a properly functioning autoconfig system in place.

1. Start by opening Thunderbird
2. If you don't already have an existing E-mail account, Thunderbird will take you directly into the wizard.
3. If you did not get taken directly into the wizard, click the Hamburger Menu → Options → Account Settings
   
4. In the lower left-hand corner expand the Account Actions drop down and click Add Mail Account…
   
5. In the Mail Account Setup window enter your name (as you wish for it to be seen by your recipients), E-mail address and password, click Continue
   
6. The screen should change to indicate that it's discovered your server configuration, click Done
   
7. Click OK
   
8. If you're adding an additional account, it should now show up in the left hand pane of Thunderbird as a whole separate account