CMS not showing in custom attribute

Good day,
I am trying to put value from a cms option on my custom attribute but the purple + button does not show in the value field so that I can select. Can someone explain what I have done wrong that this does not show in the value field. My option field is in the category cms in the ecommerce section. Is why I am having trouble?
Any help would be greatly appreciated.

Here is my public share link: [LINK](Webflow - Hippy X redo)
(how to access public share link)