Change the positive/negative slider and click where you'd like a magnet to go. The div slider is the number of checks around itself a magnet will do. The lower it is, the laggier it is. The higher it is, the slower the magnets will move. I spent a while trying to figure out why the magnets acted different from the unisprite project and how to correct it, but in the end I couldn't find an effective method of correction.
