User Data - Categories is where Users categories are created. All you have to do is to click on the new button and enter a name for the category. You can also edit (change the name) or delete categories.
...
Users categorized into different categorie categories can be seen in Agent Home - Call Handling tab. Every category is shown as a sub tab containing the assigned users. This will make things more organized for users/agents especially to make agent transfer and to check agents status and availability.