where can I find a "how to" type guide on how to manage a community as an adminstrator?

I've created one, though am a little stumped on how to proceed at this point.

The only options I see available are to edit the community description, roles, and add posts. From what I've seen with other communities, it'd appear that it's possible to have all older posts with a given hashtag show up in the community thread - which would be great to do. Would appreciate a basic rundown on this, as well as get clear on any other functionalities, etc that might not be totally clear on the front end. (i.e. can we post to a community and our own blog simultaneously, or it is either-or? etc)

Thanks!