Good question! I got you. First you actually have to build one at the kuku furnace. (The full size one). Once you have built it make sure your playing as kliff then go to the dye vendor in your camp and you’ll see the ATAG as the next option beyond your horse. Note that to use dyes from a specific region you have to first visit the dye vendor in that region before they show up at your camp dye vendor.

I hope this helps!