Joe, it is a square plate with bolts on each corner than slide through your CP. In the middle There are 4 other bolts that are used to support the trackball. If you use the plate, make sure to use a router and FLUSH MOUNT it because just dropping on a CP without flush mounting looks like ass.
Here's a photo:

Notice the square "routed" part around the cut out "footballish" looking cut-out? Being that the trackball gets quite a bit of abuse (you should see how people fling that thing in Golden Tee) I would HIGHLY recommend a mounting plate.