The interfaces described here can be used to create/delete/edit item-categories and also modify permissions on them.
Note that you need the global permission 'Can add item category' to create an item category and for the Create New... button to show up. The only exception to this is the superuser who has unrestricted access.
3. Click on the 'Create New' button to create a new item category. You should then see a modal dialog where you can add a name and then set permissions on the category.
Each drop-down will contain a list of groups. Note that you will only see groups you belong to, unless you're the superuser.
Note that you must select at least one owner group, otherwise you will lose access to the category since you're not the owner anymore (unless you're the superuser).
4. Once you're done, click Save and you should see your item category list updated immediately.
5. Similarly, you can click the Edit button to edit it later, and a similar dialog will show up. Note that, in this case, under the permissions section, in addition to groups you belong to, you should also see other groups that have permissions on that category. You will not be able to perform changes on these groups, since you don't belong to them. They are for viewing only.
6. You may also delete any category by clicking the Delete button, confirm deletion and the category list will be updated.