From Dashboard, navigate to the Sales tab

Select Coupons

Click New Coupon

Enter or Generate Code

Select Discount Type

Enter Coupon Amount

Select Redemptions Per Customer

Enter Minimum Spend amount

Select Life Span

Enter Valid Until date

Select How to Apply Discount

Add optional Description

Turn on/off Limit*

*Limit will restrict the coupon code to the selection made

Click Create Coupon