Press your back firmly against the back of the bench with your feet flat on the floor.
Hold a dumbbell in each hand, just above shoulder level, with your elbows out and palms facing forward.
Grasp a dumbbell in each hand and hold them just outside of each shoulder with your thumbs pointing in toward each other.
Simply press one dumbbell up over your head and return to the start position just outside your shoulder.
Repeat this movement with the opposite arm and continue alternating for the desired amount of repetitions.