First thing it would be best to get is a membership to the forum, not sure what level you need but there is a tutorial on fabricating trays.
Cheapest way to start would be with a router with edge guide, 90 deg V bit with a 3mm flat bottom.
You will need a work surface that is flat & rigid enough to ensure that you get an even cut all the way along with the router.
You will also need some way of cutting the composite sheet unless you already have a way to do that or buy in cut to size but that is probably another question in itself.