Training for two days, the first day of class, including teaching you how to use the cash register, the next morning exam. More than 70% of the students can go to the store for internship with their teachers, but generally those who pass the exam will be invited.
As for when to take up your post, it depends on when you finish your training. It is possible to finish the training before Friday, and those who finish the training on or after Friday will have to wait for next week, because all families are scheduled for Friday.