Coupon functionality in depth - on Membership 2 Pro - Addons

Hi there,
I desire an explanation about how coupons add-on works in Membership 2 Pro:
First of all I have a 3 month membership , so the subscriber pay the first 3 months and then he/she enjoy contents free. In this case I need to apply a discount every fees, each 3 months. When I go to coupon settings I can't see how to do that. My question is: if I apply a coupon on a membership, the discount is applied on all the fees or only the first checkout?

Thank you for your patience :slight_smile:

Rosa