How to tell which ports are being used

I'd like to start off by saying I'm not a networking person, so sorry if this is dumb.

I build and install flight simulators and I've been contracted to setup a few at a local high school running Microsoft Flight Simulator 2020. This new version of MS Flight Simulator is a digital download from the Microsoft store, there is an "offline" mode, but MS support has told me it still does require an internet connection in order to do a DRM check when the software is starting. The high school has a very strict firewall and basically everything is blocked (MS Store, xbox gaming, even logging into microsoft account) The county IT person is asking me which "port" I need access to for the software to run.

I have no idea how to figure that out? Is there some sort of freeware program I can use that will tell me which ports are being used for communication in real time so that I can just start up the software and see which ports are being used?