Choose a lit action. Its ingredients move together, in one step.
How the little post works
Each tray holds a count of letters, keys or lanterns. An action takes every listed ingredient at once and puts its results into the named trays.
Needs means an item must be present but stays where it is. Empty means that tray must have no items. A full tray blocks incoming deliveries.
Match every target count to finish. If all actions go dark, undo a choice or ask for a nudge. There is no timer. Your chapter seals stay on this device.