Advice for photographing bands at small music venues?

This is my first time, so I'm a little scared, I have messaged the bands earlier and one has replied saying that I can photograph them. I've also messaged the event hoster. I just wanted to ask what to expect? I'm planning on buying a ticket, but I don't know how close I'll be able to get to the stage. I'm also a little worried about getting in the way.