Install your certificate in Thunderbird

To import your certificate into Thunderbird go to the certificate management.

Tools -> Options           (on Linux sytems you can find the settings in the menu "Edit")

In the "Advanced" section you will find the "Certificates" tab on the right. Click here on the button <Manage Certificates>.

Under the tab "Your certificates" click the button <Import...>.

Select the file with the extension .p12, which contains your certificate together with the private key and enter the password with which you have protected this file.

Your certificate will be imported into Thunderbird and will be available for you to use.

Finally confirm all open windows with <OK> and close the "Options" tab.