You will need to know user name, the server name, and your password.
1. Open Thunderbird and Click Tools > Account Settings > Add Account.
2. You want to add an email account. Click Next
3. Put in the name you want to show on outgoing email and your email address. Click Next
4. Here you will put in your incoming mail server which you got from your Service Provider. Click Next
5. In the part you can probably leave it as is. Depending on your host it's either your username (the part before @ in your email address) or your entire email address. You can generally ignore the outgoing user name part as you will use your default outgoing mail settings. Click Next
6. The account name this is just a nickname for your account that's referenced within thunderbird by default it's the email address. Click Next
7. You will get a summary of your settings. Press Finish.
After setting up your mail account press "Get Mail" from your main Thunderbird screen and you will be prompted for the password on your newly created account. You can choose to save it or not.