Need some IT Help

Sup yall!

I was recently blessed with a job as an IT at a school. so far its all been pretty easy but i need some help understanding Port Forwarding. The A/C System at the school i work at is one of those systems which run over the network and controlled over a touch screen panel. The principal of the place would like to have access to the A/C from outside the building (from her phone/pc). How could i configure this?

Very sorry if this is a noob question.