...
When one of the Items within the “Item Group” is placed somewhere in the project, it creates an Occurrence of that Item.
Display Occurrences:
All Occurrences of an Item can be displayed in the Item module.
...
Any Occurrence of an Item that is added to a Room will be visible in the Room's Item List. The Items List can be divided into different lists.
...
Occurrence of an Item added or connected to a System will appear in the System Module as System Component (1) or Component (2).
...