eduroam participation in eduroam AU may be as both an identity provider and service provider or as a service provider only.
Service providers need to configure their wireless infrastructure to broadcast the "eduroam" SSID, and to authenticate users associating with the "eduroam" network using a standard called "IEEE 802.1x", which involves wireless infrastructure passing an authentication request to a local "authentication server". The authentication server (technically speaking, a RADIUS server), looks at the 'institutionalRealm' part of the user's eduroam username, and if the realm is a local realm for the institution, that means the institution authenticates the user. If not, the RADIUS server forwards the authentication request to national infrastructure which is responsible for forwarding onto the user's home institution.
Identity providers handle local realms, and perform the authentication of its users locally (if connecting to eduroam on the home campus), or remotely (the main use-case) if their user is travelling to an eduroam service provider.
To join eduroam AU, send your request to email@example.com. There is information available online at https://wiki.aarnet.edu.au/display/eduroam/02+Joining+eduroam+AU