How to add different downloads to variants?

-- url of the page with the problem -- : http://localhost
-- HikaShop version -- : 3.4.0
-- Joomla version -- : 3.8.7
-- PHP version -- : 7.1
-- Browser(s) name and version -- : Firefox 59.02
-- Error-message(debug-mod must be tuned on) -- : --

I building a shop selling digital products. Each product has 3 variants, and each variant has a different price and a different download. I can create the different prices, but how do I add the correct download to each variant? What I've got now is that everyone get to see all downloads. Regardless of the variant.