Adding Info

When I'm editing a person's bio and adding information I get to the Partner section and it says "Add person:" then "artist" etc. What exactly am I supposed to be doing here? Because whenever I add those words or both it always gives me the "Could not find a person matching this name" message. For example I'm trying to connect Joseph Cotten to Patricia Medina and it hasn't heard of either one of them.

Nevermind, I was able to do it by using "person:" with no space after, although it doesn't really explain it that way.