This is an excellent sushi for the neophyte. As for sushi bar etiquette, I do not believe the Japanese will be offended if you flub a rule or two. But there are a few things you must remember. The dreadful odor would raise havoc with the fine fish flavors. Please try not to leave food on your plate.
Japan is a country that has seen much famine and wasting food is a serious offense.
If you did not like a particular sushi, discreetly put it in a napkin and hide it in your purse, or better yet, swallow it anyway, accompanying it with a quick swig of beer. Think William Wallace. It is most rude. When they are not in your hand, the chopsticks should rest on the table in front of you, parallel to the table edge. Sushi is also always served in pairs.