Hi charlesced, welcome to the forum!

Alas, that is absolutely no information about the problems you are having. In your emailed variant of this question, I replied all one must need do is connect the RS-485 port (if it's an RS-485 serial network), configure the BACnet local device via either the system settings page in the old UI or the local devices config in the new UI (maybe have to enable in the edit menu page and be on an up to date version), and then create a BACnet MS/TP data source on the data sources page.

But again, without a specific question or really any hint of the problem, I don't know what help to offer.