This table explains the data between TradeRunner and WooCommerce





 TradeRunner Data   WooCommerce DataMarketplace Data
SKU    This is the WooCommerce product ID - a number generated by WooCommerce when you create a product
Retailer Reference    This is the WooCommerce Variant ID - a number generated by WooCommerce when you create a product 
MPN    This is the Variant SKU from WooCommerceMPN Field in Marketplace
UPC / EAN / ISBN
This can be set up as as a custom attribute of the product.  The name of the attribute must be one of UPC, EAN or ISBN, as appropriate in WooCommerce.     UPC field in Marketplace


This is important information to note when creating Product Groups in TradeRunner.  Product Groups require the SKU we have in TradeRunner.  Not the sku you may have used in WooCommerce Store.