i've been struggling with this, but just found out it isn't magic. By default, there is a contact info tab already installed and activated in CB. The problem is . . . it's empty.
To fill that tab with questions and such, what you have to do is, in the backend, go to Components>Community Builder>Field management.
In there, you'll be able to put individual fields in the tabs.
[Now only if someone created a plugin like mass content that enables you to create multiple fields at a time.]