In the Wind Waker, you use it by first setting the Grappling Hook to one of the item buttons (X, Y, or Z). Pressing the button you set the Hook to will open a first-person viewing window with a red dot in the center. You shift the screen with one of the analog sticks (the main stick I think). When the dot is on top of a hook-able item, it will turn into a yellow star. Releasing the item button will trigger an attempt to hook the highlited item. In combat, you can lock on to an enemy (with the L-button, press toe item button to take out the grappling hook (while remaining in third person view)and press the button again to use the hook on the enemy and potentially steal its spoil.