Hello Madiha welcome to SambaPOS forums. SambaPOS have some differences from other POS systems that you’ve possibly used before. As I’ve clearly stated in the tutorial Menu Category and Product Group have different uses in SambaPOS. Product Group is useful for reporting. For example you can group all drinks under Beverages group so you’ll see all drink sales total under Beverages group on product sales report. However you may want to break drinks into Hot Drinks and Cold Drinks (or more sub categories) on POS screen. Menu Category used for that. That doesn’t affect reports. Used only for on screen menu organization.
So whatever product groups you have you need to configure Menu Categories for your screen. To add a Category click Add Category link on menu configuration screen. If new category name matches to a product group, SambaPOS will ask if you want to add these products automatically.
These information covered in detail at Configuring Menus on First Install tutorial. Please follow that for more info.