Lets say i want to host my own instance of lemmy i will buy some domain and hosting server i will run an lemmy instance and then i can just start adding other instancies and post something on them or they also meeds to approve my instance?
You can pretty much just start adding other instances. Most of them will federate with all comers, and manually ban any instances from federation that cause trouble.
And you don’t exactly add the instances. Someone on one server subscribes to a community on the other, and the instances talk to each other to make that happen.
Most of the servers running lemmy have federation enabled and open (as you can see, I’m one of those self-hosted instances) and you can just interact with them. Some do have federation locked down, but that’s the minority
Depends. I don’t know much about the ActivityPub standard yet, but on my matrix instance I could set it up without federation, or with federation and a blacklist (blocked nodes), or with federation and a whitelist (allowed nodes).
So it depends on your setup, and the setup of other instances.
No need to be approved. Unless, of course, you do something and get blocked by some instance. There also are some instances that block everyone - I think that’s the
Private Instance
setting in the setup UI.