In my opinion, there can be 4-8 seed players in a 40-person single round, in which 1 seed is fixed at the top of the upper half (1 position), the second seed is fixed at the bottom of the lower half (position 40), and the third seed and the fourth seed draw lots to decide who is at the bottom of the second 1/4 area (position 20). Seed No.6 was drawn to the top of the third odd-numbered 1/8 area in the upper half (position 1 1), the second even-numbered 1/8 area at the bottom (position 10), and the seventh 1 in the lower half. Even numbers drawn from the lower half are at the bottom of the sixth 1/8 area (position 30), 7-8 seed players are drawn from the upper half of the remaining 1/8 area, and the lower half of the remaining 1/8 area is drawn.
Other players draw lots to decide who is in the remaining position, but in order to avoid players from the same unit or club meeting in the first round, certain methods should be taken in the lottery to prevent them from meeting and fighting in the first round.
The specific picture is as follows: (for reference) ~ I hope it will help you!