Yess its such a nice way to organize things! On your character menu go to "Manage Character" then hit "Tabs", you'll be brought to a new screen where you can create and edit tabs. 

If you want to create like what I did on my gallery with "reference" and "art" being a separate thing, you'll want to create "Sub-Galleries". If you want a completely separate tab like what I did with Naomi's "Old Design" tab I used "Full" tabs for those!