In order to create an Offer that will be accessible through a Coupon you need to
Create a Coupon
Create Coupon Items
Create an Offer that will be Activated with the Specific Coupon
Step 1st: Create a Coupon
Step 2nd: Create Coupon Items
Step 3rd: Create an offer and associate it with the Coupon
Choose Rates > Offers and click on Add Offer
Add the name of your new offer and associate it with the Coupon that you created
Choose the Offer Type that you prefer and click Next to create your new offer
As soon as you complete all these steps your new offer will be activated when a user enters the Coupon Codes that you created in the PROMO CODE field.