2mm Hex Key
The reach adjustment screw is a set screw located inside of the brake lever. You can see it by looking at the handlebar from the side.
Use a 2mm hex key to adjust reach
To decrease the distance between the brake lever and the handlebar turn the reach adjustment screw counter-clockwise
To increase the distance between the brake lever and the handlebar turn the reach adjustment screw clockwise
Whenever adjusting brakes, check to make sure the brakes function properly before the bike is ridden. Make sure the brakes can be fully actuated.