Ufriendly,
Yes it would be a query. I don't use macros, so can offer little on that.
In many inventory databases, there is a transaction file to record things like StockAdded to Inventory, Stock/Items sold to Customers along with TransactionDate, Quantity, AgreedToPrice...
Here is a thread dealing with Inventory. There is a sample database included in post #12, but the dialog/exchange in the thread may help. It shows you some interaction (confusion/clarification/options...)
Let us know how you progress.
Also: How exactly did you record your video? --well done.