Im going to my boyfriends Rosh Hashanah dinner and I have no idea what to expect! ?

I dont want to look or feel akward and out of place. I know that the candle, wine, bread blessings are said, but would I have to say anything? Do people say "Amen"? If so, when? What do I wear to a holiday dinner like this? Where does the cup with wine go if you are the last person to drink from it? Ah! Sorry, just so many questions! Im so nervous.