You will probably get the best answers from the peertube community so I suggest you crosspost your question there.
That said, I host a peertube instance. It is the same as any other fediverse service but it is very young so dont expect it to be on par with mastodon and lemmy in terms of usability.
As with all other services, you can make an account on an instance, seeing only what that instance allows you to, either by specifically allowing or disallowing other servers.
So if you want the user experience, check joinpeertube.org for a rather well connected (and or maybe large) instance and join if you want to upload content. If not, you can just use your mastodon account to follow creators or comment on their videos.
If you want freedom to do as you please, you need to get a server that is online (as in not in your home network or at least exposed but treat with caution). You can then install a peertube instance of your own, ideally with a custom domain. Then you can join the network and federate with who and whatever you like.
In any case, framatube is a great company imo but their marketing just isnt that good. Peertube has so much potential and it could be further along by now.
But dont get me wrong. It is still great and here to stay.
Good luck.
Neat. I didnt know but it makes sense I guess.