The offense sets up in a 50 alignment
When a player passes, he cuts and button hooks to the middle of the floor
Players lift up to fill the vacated spots
The player who cut to the middle clears out on the next passer
The passer then cuts to the middle
Throughout the course of the offense, players can randomly cut through the zone from the wings and the backside
Sometimes multiple players may end up cutting through the lane at the same time. This is ok. Players need to adjust on the fly to maintain spacing by either spacing out in the middle of the zone or having one of the two players clear out to the perimeter.
There are many Motion concepts that can be used in Hook vs. a zone. Some of them include flare screens, ball screens, or baseline pin screens.