Keri,
the easiest way to do this is add ANY and all relatives that you DO know about, such as parents, grandparents aunts, uncles and cousins. You then invite them to join your tree, by adding their email addresses to their profiles.
Once THEY have joined, they can add any additional relatives and information that they know of. If you get this rolling, it can very quickly snowball. My own tree went from 80 profiles to 180, 800 and 1800+
