This functionality is for Account Administrators only.
To add a new Review or Prep database click on the the database name in the top left of your screen. From here, click "Manage Account".
On the Projects tab, click on the green "Create" button at the top of the project list and a drop down menu will appear. Select Add New Prep Database or Add New Review Database.
From there, simply add your new Database Name, choose your Project, and select Users to add to the new database. Hit "Submit" and the new database will be added to your project.
Note: If you have not yet set up a project to associate your database with, you can also do so via the "Create Project" option when adding a new database.