Properly handling inventory control isn't easy, which is why I wait until well into the Developer classes to cover it. You really need to know VBA Recordsets first, or at least SQL so you can modify values in table from code. There is a way to do it without programming, but it's kinda sloppy. I may show it as an example in an upcoming TechHelp video, but you really should do it the RIGHT way if you're going to run a business on it.

I haven't covered inventory in my current Developer series yet. It's coming up soon. I just got to Recordsets in Developer 16. In my older Access 2003 lessons, inventory took me 4 classes (Access 326-329) to cover properly. I'll be revising all of these lessons for Access 2019 over the next couple of Developer lessons, so if you want to start learning this stuff now, grab Developer 16 and 17.

I will be including proper inventory control as a module in the ABCD after I build the order entry module, so that's going to be a little while. Hopefully I'll get to it in the next month or two.