A good starting point is to download this free app
and run it from a laptop on the same network as the BACNET equipment is supposed to be. If this tool finds the points, then Crestron will find them too. Then you have to decide if you have more than 50 points, in which case you need to pay $500 for a license. The BACNET implementation in 3/4 series, as many have found is clumsy in the extreme to program. The Cool Automation interface is your friend. It makes it MUCH simpler and faster to program
OP