Making the slots in the chest armor

I've recently just started on my Boba Fett project, beginning with the armor plates, and wondered how to add the slots in the chest armor for the led display, before I begin on the paint job. I'm not quite sure how to do this properly, and I'm kind of scared I'll damage it. (I accidentally made a crack in my Stormtrooper helmet before while assembling it, thankfully that was underneath the ear-pieces and thus fixable.)
Anyone have any methods and/or tips?
The plates are just the plastic(sintra) kind, not resin.

dude jusat cut them out with an knife of some kind just be very carefull while cutting,then sand thethe edges a bit to get the shape just right and thats it but be really carefull while cutting

do a search for TDH Member, SUPERJEDI. He is the master, and has done a tutorial on this. He actually assembles and painted my armor.

Use a dremel tool a knife is kinda sketchy...use some painters tape where u want it mark the hole on the painters then cut the hole out with the dremel

A dremel tool sounds good, seems more reliable then trying to do it with a box-cutter knife. Thanks for the idea, gonna see if I can get my hands on one of those.

I'll look in the tutorials. I haven't worked much with 'hard-part' costumes at all, so I'm pretty new to this.

Thanks guys.

I cut Sintra with an X-acto all the time. Don't try to cut through all in one slice. It takes me 5 or 6 slices to get through 3mm Sintra. Use a straight edge to keep your line straight and use a brand new blade. If you have a dremel, that's probably work better, I don't, so I use a knife.