We are running a promo for a specific brand where if you buy 3 of a specific style chair you get 1 free. This is what I have set up: https://i.stack.imgur.com/NkqrU.png
There are lots of colour variations of the chair so I have input all the skus, as it didn't work when I used the SKU of the default product that they are all associated with. I also changed the 'x' to 3 as I wasn't sure if it meant 3 or 4, but that doesn't work either. Any ideas?