please give some advice about table manners in Japan?

It is acceptable to eat sushi with one's fingers, rather than chopsticks, if the dining situation is relatively casual (this also applies to dining out at kaitenzushi restaurant).
Never place chopsticks stuck vertically into a bowl of food, as this is the traditional presentation form for an offering to one's ancestors.
Accepted practice in helping oneself to a communal dish such as a salad, is to reverse the chopsticks. However this is regarded in an all male, or casual situation, as too formal and additionally, a female habit.
Women should cup their hand beneath their serving when using chopsticks when conveying food from dish/bowl to mouth. Men should not do this.
In communal dining or drinking, the youngest person present should pour alcohol for the other members of the party, serving the most senior person first. The server should not pour their own drink, rather they should place the bottle of sake, beer,wine or spirits, back on the table or bar