The coupon generator plugin allows you to provide coupons to your channel users. In order for the plugin to work, you will need to provide your own coupon generation functionality in a form of a REST API service which plugin will call in order to get coupon codes for users.
The API endpoint exposed by your API service will be call each time the user requests a coupon code, under the condition that user is allowed to request a new coupon code.
For more information about the REST API service you need to provide, see the API reference section.
To know more about the coupon generator plugin, see your channel's admin panel.