Access 2013: Use macro to update table based on new entry

I'm trying to get a macro for 1 table to update another table based on the latest entry by the user.

I have 2 tables.

Product(ID, Inventory)

and

Sales(Sales ID, Product ID, Amount)

I created an "After Insert" macro on a Sales table which looked like this

For Each Record In Product
Where [Product].[ID] = 1
    Edit Record
        Set Field
            Name Inventory
            Value [Inventory] - 30

What I want to do is that the condition on "Where" should be comparing [Product].[ID] with the [Sales].[Product ID] of the latest entry which triggered the macro and "Set Field" Will update the Inventory with the current value of [Inventory] minus the amount sold on the latest entry.

Can that be done in Access? I've done SQL but it doesn't seem to help here.