Applying discounts to an offer

Summary:

Hi, I wanted to ask you for help about applying discounts to an offer, I was trying to add a discount by using the "View or Edit Alterations" option in the pricing section, but I keep having issues by doing this.

Content (required):

First I try to add only the Name, the Alteration Type and the value of the discount, like in the first image attached but it didn't work. Then I try to add values in the section below (second image attached) and I realized that when I save the alteration, the changes on this section are not applied and the issues keep appearing. I don't know if that is the right way to apply a discount or if there is another way to do this.