pretty much. if you post to a community regularly it will eventually get noticed as many people peruse all. I advise posting regularly over timeperiods than all at once. again since people peruse all getting slammed form one thing can annoy folks compared to seeing it over time. you make a community on instances. instances decide what they allow or not. you could make your own instance if you wanted to but you would need hardware or vms and administer it and such. no real need as there are a lot of instances and most aren't all that picky. might have a hard time if you want to make facist or alt right or such but there will be instances that will allow it they just are defederated from normal instances.