Standing with your feet spaced shoulder width apart grip the dumbell securely with both hands, bringing it up and onto your shoulder. Your grip should have your thumbs overlapping and fingers gripping around the top of the dumbbell. Then press the weight up and off your shoulder, centering it with your spine.
Start by pressing up until your elbows are almost fully extended, then slowly lower the weight behind your head until your elbows are at a 90 degree angle or just past. Maintain an activated core throughout and conduct the movement at a controlled pace. Repeat for the desired amount of repetitions then rest the weight onto one of your shoulders and bring it down safely.
Avoid excessively leaning back causing imbalance, brace your core to keep a straight spine.