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
Enter the PIN using Cryptoucan’s keypad
That’s in the bottom right corner of the keypad