First pin the cable height to the middle position then pin a suitable lifting weight. One at a time, grab the cable handles and position yourself in the centre of the cable rack, just forward of the rack line and pulley lever.
Your core is tight and your arms will be outstretched, angled slightly back behind your body with palms facing forward. You may choose a symmetrical stance with the feet just outside shoulder-width or an asymmetrical stance with one foot forward in front of the other, which ever lets you feel more balanced. This is your starting position.
With a slight bend at the elbow, squeeze your chest to bring your outstretched arms together in front of your body at around nipple line, over 1-2 seconds as you exhale. The body remains stationary as your arms draw a large arc from the shoulder joint. Pause and squeeze for a brief second at the end point of the movement where the cable handles meet in the middle and the palms are facing each other.
Now reverse the movement inhaling as you do, bringing the chest back to full expansion with arms outstretched. You should feel the chest muscle being stretched and opened right up.