What should I expect from a buyer's agent?

If I am a first time home buyer, what should I expect from my agent? I know the process is 1) figure out my needs, price range and area; 2) send me the listing; 3) show me the houses; 4)offer and negotiation; etc.

For instance, when showing a house, what kind of information/homework my agent should do, what kind of information he/she can disclose? Obvious I am a first time home buyer, I might not ask a lot of questions. How's a typical/correct house showing look like? Can you describe? Is there a redflag that I need to be aware of?

If I am lucky enough, and I find a house I liked, what should I expect from my agent at stage 4 (offer and neg)? How can I tell if my agent is trying his/her best to protect my interest?

Can you shed some lights on how to find a great agent?Thanks!