Morse Code is a backup access mode. It allows you to unlock your device using long / short combinations by pressing down on the shackle. Morse Code gives access to your lock without your fingerprint or your phone.
You can set up your Morse Code in the "Setting" section within the mobile app while your lock is connected. Once Morse Code has been set up, press down on the lock's shackle three times to enter Morse Code mode. The status indicator light should be purple. Under Morse Code mode, you can enter your combination by pressing on the shackle again.