I am trying to add a line item number to a subtable. (The database is based on the Sample Invoices template). In the template, each item on the invoice has a sequential line number added automatically. I have studied this, but I can't see where it is being created. Currently, I have to add the line number manually. I need this to keep the items in the table sorted in the order I want.

I feel like it is something simple that I have overlooked, but I can't spot it.