2. Taking hold of the Booster, remove the top, and screw clockwise onto the neck of the Concentrate, until you feel a click. 3. Intelligent dosing system: the correct dose of Booster is mixed with the Concentrate (6 ml). 4. Wait until the flow has stopped, and unscrew the Booster. 5. Make sure all product is drained from the bottle neck. Screw the top back onto the Booster, and turn it upside down on its base. 6. Screw the spray head onto the Concentrate, and shake to mix. Spray the entire contents of the vial, 10 cm away from washed and towel-dried hair. Massage through lengths. Do not leave on. Rinse thoroughly.