The standard drawing item reference is used to refer to a pre-defined assembly or collection of parts in a standard drawing. You first select a standard drawing from the “Select standard drawing” button. After you have selected, the Select Part View shows all items in the drawing.
The BOM Tree tab will show the hierarchy of the drawing items navigated by PowerBOM.
All these items shown will be made part of the calculated BOM and form part of the drawing item material list.