@parker5095  RE: The link recommends using Excel to load the sample files. What it doesn't state is how to save them. I know it's not supported, but can someone who's used it share what you do?

While it's not the best way to create an IIF file, you can save a worksheet as an IIF file.

To save a worksheet as an IIF file, choose the Save As option (File | Save As when using Excel 2016), then click Browse, and then pick "Text (Tab delimited) (*.txt)" as the "Save as type:" and then give the file an *.iif extension.

It should look something like this, depending on your Excel version and OS:

It's easier to defeat Excel's default file extension if you enable viewing of known file extensions, like .txt and .iif, among many others. To do that, see instructions at the bottom of this page on our site: https://bigredconsulting.com/how-to-select-the-correct-company-file/