It’s in the upper right corner of the window
This will open its sub-menu
This will open its menu
Fill in the name of device’s holder
Use the standart ISO 639-1, e.g. en, cs, de, pl…
Thunderbird will ask you for your PIN everytime you’ll try to sign an email
This will prompt you to enter PIN on your Cryptoucan
Confirm it by pressing the hexagon symbol in the bottom right corner of the keypad