In this video, inventor Brian Green demonstrates how to brake on Cardiff Skates.
To brake, put one foot forward, lift up its front wheel, and apply some weight on the back wheel. This will engage the brake.
The best position is one where your knees are bent and the rear wheels of your front skate are aligned with the front wheel of your back skate.
You can brake with whichever foot is most comfortable.
Learn more about Cardiff Skates at cardiffskate.com