Inventory Tracker Sheet Help

Hey there,
New to the forum, still trying to fumble my war around Excel as well.

I'm currently using Excel and the app & excel add-in (SCAN-IT to office).
Currently with the phone app, I can first select whether the barcode scan will add or subtract (-1 or 1). I then scan the barcode, and whichever cell is selected in Excel will received the numeric barcode, and the cell to it's right will receive the value or -1 or 1. I'd like to have this cell add or subtract from our current inventory. Is this possible? If so how.
Maybe I'm using the wrong barcode scanner app too.
Please see sheet attached. For privacy i changed all products and reference #'s to placeholders. but this is EXACTLY how the sheet will look in order.

Welcome to the forum!
Not sure I understand what you are trying to accomplish.
What is the expected result and in what column/row is it to be calculated?