The disc is brought into the game on the sideline. The vertical stack is in the center of the field.
The second handler initiates play. If they catch it on the up line cut, the last player in the stack continues deep.
If the second handler (2) does not get it, the 1st in the stack (3) comes back into the center to reset the disk.. (2) comes back into the stack to replace (3).
(5) and (6) now initiate play for a centered disk.
If the disk is caught, (4) continues.