When you are standing beside a bike, you can unlock it by tapping the "scan QR code button" at the bottom of the app home screen
A camera mode will open, and you should point your phone to the QR code on the handlebars or on the rear of the bike. When you scan the code, you will hear the unlocking sound after a few seconds. You can also simply select the bike on the map and click "Start the ride".
In case of the lock does not open, please end your rental and try again on the same bike or a different one. You can also report the problem to us at the last screen after ending your rental.
P.S. Before you start please make sure that the bike is in good condition. You'll have 2 minute free to return the rental in case there is an issue with the bike