To add more codes to an existing discount set, you can easily do so from the dashboard. First, find the discount set in the list. You can change the list's sorting behavior and click through pages with the actions below the list. Once you've found the discount set you'd like to add codes to, simply hover over the row and click the Add codes action that appears. You will then be able to specify how you would like to add codes and the form will remember your last used settings.
If you need to change details of the discount itself or would like to export all of the codes for a particular discount, you may do so from the discount details page within the Shopify admin. For convenience, we've added a Go to discount hover action on each discount set to take you directly to the corresponding discount. The third hover action is to delete the set. This action will delete the discount set from the app, but the corresponding discount and all of the codes stored within Shopify will not be deleted. You may later choose to delete them from the Shopify admin, but the app will not do so to maintain your data and reporting within Shopify.