I actaully want to know how as well
It's being tested on a few selected wikis and is not available for everyone at the moment.
You can't add it. FANDOM staff coordinated with some wikis to add it. You can contact FANDOM staff and see if they will let you use it, but have not heard of any smaller wiki successfully getting it by request.
It's been in "beta" for years.
Which wiki is this on?
What do you think?