After the group purchase, you should receive a short message with the order number and so on. If you go to the cinema with this single number, the cinema will have a window dedicated to group buying. Go to the window and say it's a group purchase. Give them a unique number. The seat was chosen by the window. As long as no one can choose a seat, the sooner you choose a seat, the better. It is recommended to choose the middle and rear position, not too far ahead.