Go to the profile you wish to add to. At the top are tabs: Profile (public view), Edit, Images, Family Tree & Tools, Changes, Privacy, and Profile (private view). Choose the Edit tab.
Scroll down the page until you find a large(ish) text box. That is where you will put the category that Lucy gave you - right at the top of the box, above everything else, so
[[Category: blah blah blah]]
==Biography==
a story