The acrylic should turn up with a thin protective pvc foil layer on both sides which helps protect the polished and plated surfaces. To cut the plastic use a jigsaw fitted with a relatively fine wavy set metal cutting saw blade, protect the surface by applying a couple of layers of wide (2in) masking tape to the underside of the saw base (to cover any burrs and/or sharp edges there may be), turn the blade orbit off and finally spritz/dribble water continually onto the cutting line to reduce any tendency of the swarf to weld back onto the main sheet.
IMPORTANT: Using water with any electrical tool is potentially highly dangerous - use a battery (cordless) saw if at all possible, if not then always use a tool which is protected with a sensitive in-line RCD. Either way ensure that as little water as possible contacts the tool by spraying the workpiece and not the tool
Cut carefully the edges can be cleaned up using a properly burred (sharpened) cabinet scraper (hint: place the plastic flat on a work surface and pull the scraper along the edge towards yourself). Set the factory edges to the top if needs be when installing
A better quality of cut can be had by using an electric router and ideally a spiral HSS router cutter, again with water cooling (same precautions apply)
Note that when cutting acrylic a lot of heat is generated, so cutting at the fastest possible feed speed and lowest rotation rate for the router is recommended (in any case no more than about 15,000rpm, ideally less - if your router is a small "screamer" running at 27 to 30k rpm, find another way of cutting because it will weld the cut in next to no time - too fast)
If it is too much of a faff, get it cut for you by the supplier (many plastics firms hsve cutting and polishing services)