Keeping it simple looked a bit hard for me... I remember in older versions of Alteryx that it was possible to edit the query and select a specific cell, but it seems that this is no longer available (possibly due to the fact that the JET drivers are deprecated).
This challenge was a pretty good reminder of using the Directory tool just before the Dynamic Input. For someone just getting to know this tool, the hardest thing to understand would be to identify which string to update on the SQL statement; on this case, Book1.xls would be replaced with FileName. It was fun.