At the link you add, on the section "Listing your items" thay say:
"Select the category or categories for your new listing. If variations are supported for those categories, you'll be prompted to choose whether you want to create a listing with variations. Select Yes and click the Continue button."
I did select categories for my listing (Skin Care > Samples & Trial Sizes) but never prompted nowhere which gives me the option to chose Yes or No for creating listing with variations.
There's no reason why this option shouldn't appear for these categories.
They note that only the Best Offer and Lots options aren't available when listing items with variations at the moment, but I didn't chose these categories anyway.