You can cut ACM panels a number of different ways. Many professional companies use a router. You can buy a circular saw blade made for aluminum. You can use a jigsaw as well.
In this video I show up a very simple way by scoring and snapping using a razor knife and straight edge. If you were cutting a larger piece or a longer cut I would recommend a couple of clamps to hold one end flat to your surface.
After the cut you'll want to knock down the cut edge to make sure it's not too sharp. after this video I used the back side of the blade a pair of scissors to smooth the edge.