PowerBI: STOCK TURNOVER ANALYSIS

Is there someone here who uses SAP Business One and Power BI?

I want to ask something about the standard STOCK TURNOVER ANALYSIS Report. I am having difficulty in thinking on how to load the "Average Inventory" of an item -- Average inventory = (Beg Inv + End Inv ) / 2 to Power BI. In SAP, you will be required to input the Start Date and End Date, then the SAP report shall give you the inventory details based on those dates. I wonder how to do that through PowerBI. Thanks!