Tab: Business > Cart. Each ordering module that is active on your account gets two rows (global only):

• <Module>: Item Minimum per Checkout – e.g. A la Carte: Item Minimum per Checkout, Catering: Item Minimum per Checkout, Grab&Go: …, Realtime: …. Default 0 = no minimum. The customer must add at least this many items from that module.
• <Module>: Amount ($) Minimum Value (excluding tax) – default 0. The subtotal of that module must reach this amount.

If you have created extra A la Carte-style menus, each one gets its own pair of rows named after that menu's title. When a minimum is not met, the menu page shows a reminder and the cart blocks checkout until it is reached.