Power Store does not have the ability to easily import products using a csv file. Batch imports "can" be done, but they are not supported and problematic at best.
See this post for a sample export of the products tables to MS Excel format:
I have found the easiest tool for doing an import is PHPMyAdmin. I say easiest, but it is still not simple.
In Reality, the best way to get product information into power store is to manually add each one using the Admin pages that are provided.