Out of the box BigBlueButton wants to run with FreeSWITCH on the localhost. We like to spread out the load, different boxen for Redis as well as FreeSWITCH (and post-processing)
I'm assuming you've already got BigBlueButton installed on one machine. You can just duplicate that installation on another, like mirror each other - unless you already have an FS box ready. I'm going to assume you're starting from the BigBlueButton installation of FreeSWITCH.
For this installation $hostA is your BigBlueButton system, $hostB is the IP of the FreeSWITCH. I'll extend these vars with _<name> like $hostA_ip - should be obvious.
Basically we've got to make it listen on the network, not just local host.
Just update the configuration to point to $hostB_ip, easy!.