STARTING POSITION:
Sit on the bench with backrest in front of the Smith machine and place your feet flat on the floor. Select the appropriate plates amount to put them on the machine. Grab the barbell with prone grip and place it just above your shoulders, under your chin. Your hands should be slightly wider than shoulder-width apart. Press your head, upper back, and hips against the pads. Contract your pelvic floor and core while keeping your chest up. Lift the bar just a little and twist your hands to un-rack the bar.
MOVEMENT:
Extend your arms to push the bar straight up until your elbows are extended but not locked out. Slowly lower the weight until your hands are just above your shoulders. Make sure you don't arch your back when you perform the exercise. Repeat the movement until all repetitions are completed and then re-rack the barbell.
TIPS: The exercise key is quality over quantity. The trick is to perform the exercise using proper form.