Sit upright on a bench and hold a dumbbell with both hands
Lift and hold the dumbbell overhead, with arms fully extended with palms facing the roof and elbows pointing forward
Keep the chest up and breathe in on top
Lower the dumbbell behind your head by bending at the elbows
Lower the weight as far as possible while keeping the shoulder position fixed
Come back to starting position by extending the elbows
Finish the rep by squeezing the triceps
Breath in and repeat