@Shewolfnm As far as I understood, anyone can make a group, but it may take some time to be approved, as this has to be done manually.

Also they state that mastodon (which is only one part of the fediverse) works best and other platforms (e.g. friendica, peertube, ...) may not be able to follow the group.

I think the term "server type" in this sentence may be a bit misleading --> "If you are using another server type across the fediverse, you may be unable to follow these groups."