I probably did not understand how it works ...
I create a coupon buy X get Y, where Y has 100% discount; when using the coupon code the product Y is automatically added to the cart but is still at full price, to get the discount you have to enter the same coupon code again and this time the discount is applied.
I would like when the product Y is added already had the discount applied.
I set the "process type" to "smaller value"
Also I would like to know if I can also use this coupon for all "child" variant of single product or if I have to make a coupon for each variant. :-(