"Like on all fediverse services, as a Hubzilla user you have the choice between different servers, called hubs. Some of them are not open for registrations (these are also called "private" hubs), others allow registrations only by approval through the administrators, and again others are completely open for registrations (these hubs are also called "public")."
To start in Fediverse is different to centralized systems of big companies. Whre you are in a mass of users but still in a cage you can enter at Fediverse a free wild life of beeing there you want and connected to everybody and across platforms. That means, you can reach a video tube (Peertube), a picture show (Pixelfed), a microblogging (Mastodon) or a classical social media (Friendica, Lemmy, Diaspora or Hubzilla for example).
Be open to develop your life and your mind!
"It is primordial for a Hubzilla user to choose the right hub. It may take some time to find the hub you can rely on and trust its administrators, to be sure your data is safe. Best is if you know the administrators' characters and how they works. After having selected potential public or approval-requiring hubs which might fulfill your needs, try to contact their administrators and ask them about their commitment: What's their purpose to run that hub and how do they get a remuneration for their commitment? The best case is when administration is done by a team instead of by only one person. Observe their communication style: How do they announce updates and changes concerning their hubs and how do they handle support requests by users? Of course these questions are answered best when you know the administrators in person.
When not knowing an administrator in person, it might be best to start – before building up your channel, profile and connections seriously – as a reluctant / guarded user to test the hub's functionalities, while being still careful with your sensitive data."