Go to: Reports > Reports > Sales Analysis > Product Sales Report (alt R R S P) 

Import XML Report Design: Download NY Times Best Seller sample xml File

This needs to be submitted weekly, starting with Sunday to Saturday.

Report format is sorted by store, then most sold to least sold for any product greater than a single sale.

It is designed for portrait layout.

Submit it, then preview.  If meets your needs, back up one level to chose print/preview, and select ‘CSV’ in the power bar.  It will prompt you where to save and what to name the csv file. 

This is a single report for both stores.  If NY Times Best Sellers List want 2 separate files, let me know and I will walk you through the changes needed.

When running the report you must set the "Show products by option to "Product" in order to combine both stores into a single line.