CSV, XLS, and XLSX are all supported. However, CSV is most reliable.
Maximum file size is usually 2MB. CSV files may be zipped to reduce
The purpose of the preview screen is to specify the format of your
file. It shows the first five rows of data with dropdowns above each
column. Use the dropdowns to specify what (if any) data is present in
each column. For example, if UPCs are in the 3rd column, set the dropdown
for the third column to UPC.
Large files may take awhile to process. Give it 5 or 10 minutes before
deciding it didn't work.