How to add error redundancy to current Power Query code if data source is empty

Hi Dino,

First off, thanks for helping out. I really appreciate this!

1. I have a question about the "data loading query". You mentioned "but make sure to check for null before proceeding". Am I suppose to add something else to the query on top of what you alrteady stated?
2. In regards to both the "data loading query" and "the helper query", I am not getting any syntax errors, but I am still receiving the expression error for queries that cannot locate a data file. Is this related to the question above?
3. After updating the query with your updates, I click "Close & Apply" and I get a Load error "There weren't enough elements in the enumeration to complete the operation.". Most likely related to the null values issues, but not too sure?