OK. Here's the way it works:

1. You set up the link by creating the query (which I have done for you).
2. You then set the query to update (refresh) either manually, or automatically when you open the file or every so many minutes.
3. Edits to the output file do NOT affect the source file, however edits to the source file DO affect the output file when refreshed. You should not (need to) add any data to the output table, as it will not survive a refresh: there are ways round this, but it adds complexity.

My understanding was that you wanted to extract just the columns of data needed to populate your invoices, so no tweaking of the output data itself would be necessary.

YOu need to play with it to understand it. If there are issues with the way it works for you, then you will need to explain your exact workflow in more detail.