Adding more than one family member

[KleinpezFamily]

I just upgraded to Family Premium and sent an invite to one member of my family. I would like to add others but when I try to do so the only option provided is to replace the current family member. The Help pages show a page with "Empty Slots" to add additional family members but that page does not show for my account. I get just the one family member and an option to replace them. How do I add more than 1 family member to my account?