Setting up the discount
Go to Orders > Customers and select the customer you'd like to add a discount to
Once you've selected your customer, choose 'Discounts' on the left side
Enter in your desired discount amount. For example, 10% would be entered as 10
Be sure to save!
How the discount works
Go to your Take Order screen and search for the customer you just edited
When you enter in a product, you will see that the discount amount is automatically taken off!
Process payment as usual