Basic rules pretty much include that you're not allowed in someone else's dimension unless they say you are allowed. A nice tip would be in the first post of your topic to make a list saying who's allowed and who's not. Then, other people may make portalling free to anyone and anyone could arrive at their place. It's the creators' choice.
You may have more than one, but don't over do it. Three at the most (this can vary), but you must ask for permission for each world you would like to make. Just provide a small summary is all we ask. 3nodding
All rooms must be tagged by a mod. You cannot do this yourself. Only a mod can. If you do this yourself and it's found out, you will be given a warning. Tags are just a note in the first post of your room that say ((Tagged -