Hang from the bar in an active shoulder position, squeezing shoulder blades down and back. Initiate by swinging your feet backwards and forwards. Follow the swinging motion with your hips and shoulders making the shoulders the pivot point. Once the swing is controlled and the bar is in front of your bodily you will quickly pull the bar towards your chest followed immediately by a quick push away from the bar that will return you to the same point where you initiated your pull. If done correctly you will be able to link directly into your next pull.
This movement takes time, strength, and skill to develop.