Supposing that you found a profile for Stella's father:
Since you are a profile manager for Stella, you should see a father? hyperlink in the space where the father's name would go. Click on that link to open a screen where you will be given an option to "Connect an existing profile for her father." Select that option to get to a form where you can entire the father's ID.
To connect somebody to a profile that you don't manage, open the EDIT screen for the profile. On the right-hand side you will see hyperlinks to adding various family members.
