Setup for the lat pull down by attaching a wide grip  bar to the machine, selecting the weight you want to use, and adjusting the thigh pad.  While standing, grasp the bar with an overhand grip at wider than shoulder width apart.  Holding the bar, sit down on the machine.  This should take the weight off the stack.  Keeping your back straight, eyes facing forward, and without leaning back, slowly pull the bar down to your upper chest.  Do not let the bar touch your chest.  Pause, and slowly lower the weight back to the starting position.  Do not let the weight touch the stack. (Repeat for desired reps.)

 

A huge problem with the lat pull down is that most people can not isolate the lats and end up using their biceps or lower back to do a lot of the work.  To isolate the lats, use a wide grip and when you're pulling down, focus on your lats pulling inwards as they go down and pull your elbows back behind you.  It's also common for some to lean right back and swing down the weight.  You will not get the maximum results from the lat pull down using this method.  Keep sitting upright throughout the movement.  Finally, if you find your forearms are burning out before you finish the set;  grip with bar with a "overthumb" or "hook" grip.  This means you do not place your thumb around the bottom of the bar or handle.  A hook grip takes some of the strain off your forethumb around the bottom of the bar or handle.  A hook grip takes some of the strain off your forearms when performing pulling exercises.