Have you looked at this page?
https://www.wikitree.com/wiki/Help:Person_Profile
further down the page is this heading
Creating New Profiles of People
Plus
If you are adding a family member to an existing profile, click here.
If you are creating a profile of an unrelated person, click here.
If the profile is for someone unrelated it takes you directly to the create new profile form, and then you fill in the spaces with the information asked for .
If the new profile is for a family member of someone who already has a profile, go to that person's profile, where you will see, options such as add a child, add a spouse, add a parent etc and then you fill in the spaces with the information asked for .
Remember you must have a source for each new profile you create.
if you need help with sources go here
https://www.wikitree.com/wiki/Help:Sources_FAQ
If I have somehow misunderstood your question, then come back here and ask more questions.