@egenard2u Not sure if you ever figured this out or not but I just happened to see your question.
In the tutorial the only thing you would need to import would be the collection. This isn’t super clear when I was reading though it though.
The other files, the JSON and CSV are to be used in the collection runner for the Data file. Basically the contents of those 2 files are identical, data wise, just in different supported formats.
When you run the collection runner with either of those files it will cycle though the call for each row in the CSV (minus the first row) or each element in the JSON until it has completed.
Hopefully this helps a bit.