"Nine knowing" means knowing the number of people attending the banquet, the number of tables, the organizer, the invitee, the identity of the host and guest, the standard of the banquet, the starting time, the types of dishes, the order of dishes and the charging method.

"Four understandings" means understanding the religious beliefs, customs and habits of guests and their life taboos. Understand the special needs of guests and the arrangement of meetings and rooms.

See the website for details.

Brother, remember to add points next time you ask such a professional question.