The Mercury Loyalty program allows customers to earn credits with each purchase and earn discounts over time. To use Mercury Loyalty, you must first set up your loyalty program in System Settings, setup a View Loyalty Info button on the Front End, and set Section/Table Maintenance to Prompt For Customer Before Tender.
You will also need to configure a View Loyalty Info Button on the Front End and configure a Discount Items button to apply a specific discount to the entire sale.
Discounts for the Mercury Loyalty program are created through Mercury. Contact Mercury for instructions on how to create discounts.