Start this movement by gripping the inside of the bar with one arm. Your stance should be straddled over the bar.
Begin this movement by breathing and bracing your abs. As you row the weight up, keep your upper body more upright, and pull using your back. Your arm should just act as a hook.
Once you reach the top position, squeeze your back muscles. Lower the weight in a controlled manner and get a good stretch in the lats at the bottom before starting the second repetition.