[i]joinCriteria[/i] - The SQL to join the table you want to search and the modResource table. Your table must have some connection to the Resource it's on (otherwise SimpleSearch won't know how to load a URL for it!)
https://forums.modx.com/thread/98382/how-to-search-website-for-product-names-on-dynamically-created-pages#dis-post-532255