You want to create your own article group. In reality, this is not possible in Winner Design. However, there is an alternative that is to rename an existing group of items that you don't need.
- Click on Global settings in the menu bar and select System Settings.
- Click the Item groups tab
- Choose the Item group that you do not use, whilst taking care of how it works regarding the selected VAT profile.
- Having made your choice, rename the selected Item group by changing its name in the Printname column.