Bartolomeo is not Australian but European. It's a platform designed by Airbus DS. It will be installed outside the Columbus laboratory on the COL-EPF (Columbus Laboratory Module Exposed Payload Facility).
This platform will be installed, serviced and operated in a collaborative public-private utilization scheme with ESA, NASA, and other partners in the ISS program.
The Australian FAST mission is a payload on this platform. FAST is organized by Neumann Space - they needed some space on the Bartolomeo platform to test their ion drive and bought more space than they needed. FAST allows other companies to 'rideshare' small experiments with Neumann's ion drive.
Companies and institutions buy space on Bartolomeo, Airbus DS handles the launch, installation etc.