I know I am a little bit late, but I am not sure that my experience will help a whole lot anyways. The last time that I hunted Miller Island was before the draw and it was simply first com first serve. We would line up at 0'dark thirty and wait for the kiosk to open in the parking lot. You needed to have your license and validations ready to go for sign in, which was about a half an hour before shooting light I believe. They would verify your validations and they would let you to choose a zone based on available room. Then it is off to set up and start watching the skies. Checkout was fairly simple. You stopped by the kiosk and showed them any birds that you might have harvested.
I don't if they still do it this way, but certain zones had time limits on them for how long you could be there. If you chose one of those, and your time ran out, you would have to pack up and head back to the kiosk to see if any of the all day zones had available room.