Your name:Type in the name you'd like to appear on your emails.
Email address:Type in your email address.
Password:Type in the password for your email address.
This warning states your not using a secure mail server. Mozilla Thunderbird explains it here.
Why does Thunderbird warn me that my server doesn't use encryption?
To continue creating the account you can place a check mark next to I understand the risks.
Click the Done button.