17 badminton match, how to make a double elimination system to decide the top 8? How to see you again?

First draw lots ... draw lots by bye ... The remaining 16 people will start the first round ... then nine people ... the first draw will not take part in the second draw ... the remaining eight people will draw ... then goodbye ... then the second round ... then five people ... play games in a cycle ... The top four will be eliminated again ... and finally the final one will be made.