Etiquette means the rules or norms (written or unwritten) of polite behavior within a social group. There are three significant sources of Stack Exchange chat etiquette, listed in order of highest priority.
Norms formally established by Stack Exchange Inc. (the owners). Whenever there is a potential conflict of norms, these take priority.
Local social norms ...
What is the best use of chat vs when should you post or comment?
A rule of thumb (which I just made up) is, if what you have to say is oriented toward the site -- for example, you're pointing out a logical or factual error in a post, or asking for clarification -- then it should stay on the site, i.e. as a comment. If what you have to say is oriented toward ...
You're right to want to come to chat. It's a wonderful place where lots of great and constructive discussion happens.
To find your way to chat you'll have to look at the top of the site, to the left of where your avatar is:
There you'll see the Stack Exchange logo. Click on that and a menu will appear.
I have highlighted there the link to chat. Click on ...
There's a post on main Meta about this, from Community Manager bluefeet. I've copied it pretty much verbatim below, as it seems to answer your questions about what a room owner can/can't/should do.
As for your last question about finding and identifying room owners, they're listed on the info page for a given chatroom. E.g. for the main ELU chatroom:
As you note in your question, it is possible to edit your messages, within a 2 minute window of posting them.
There are two method's for editing.
The easiest is to push the up arrow key ↑, and that will put your last message in the text box for creating messages.
You'll notice that the background of the text box is darker now that ...