Dude,
Go up a few post to Tequila's post with pictures. I have the version second one from the right with the "hooked" jaws to grab the coils. One is shorter and one is longer to equalize the puller into the center of the spring. You need to connect the jaws to the spring and then rotate them down to the point that they pinch the bottom spring coil and the top coil. Basically spin them up the coils until the reach the very top and bottom coil as they hit the top and bottom end of the coil.
This gives you maximum compression and I have yet to find a coil spring that compressed this way will not "fall out". The trick is to achieve the same compression when you go back in. If you go for to much compression length the coil may bind on the jaw and prevent it from spinning down to remove.
Rob