In BoosterHub, each person in the database is identified by their unique email address. For connections such as family members, you will add Relationships. To add Relationships, go to People > Add Contact. Scroll down to the lower right corner to click the big, blue + (plus) button to add Relationships.

If you are editing a contact that has already been entered in your system, go to People, click on the person, and select the Edit this Contact icon at upper right of the screen.