Start from where hands are, not from the menu. Typical splits:
Hot / Cold / Expo for most full-service kitchens.
Grill / Fry / Assembly for burgers and fast casual.
Bar as its own station wherever drinks are made away from the kitchen.
Uncategorized items appear on every station, which is useful for items like sides that anyone can plate. Give everything else a category in Square so it lands in one place.