Jeez, are you deliberately trying to make this difficult? WE NEED DETAILS.

Where are you trying to access from? Mobile? PC? Mac? Something else?
Do you have VPN access to your internal network?
If your BAS behind a firewall?
What are your security requirements?

BAS is just a website. Access to it from outside of your LAN would depend on your network configuration.
Talk to your network admin and explain what you need to do.