On page 2 of the of this module it has you creating a lookup table file and then a Lookup definition.
When you successfully create the table file and try to create a definition that points to that CSV the file is missing from the drop down menu.
From the search I had to enter "|inputlookup products.csv" which displayed the contents of products.csv and then when I went back to the definition creation I could select products.csv from the lookup file selection.
Hope this helps someone else.
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