If you want to set a minimum order amount you may do so in your Delivery Day settings. An order minimum will prevent customers from placing orders for that delivery day unless they meet the minimum purchasing requirement.
1. Navigate to "Deliveries". Click Market Admin>>Markets>>select your market>>click on the "Deliveries" tab.
2. Next, click into a delivery day. From there you will see the box where you can add your order minimum dollar amount for that delivery option.