https://connectebay.zendesk.com/hc/en-us/articles/115001791752-Quick-Start-to-Selling-on-eBay-from-Shopify
Bulk edits>
https://connectebay.zendesk.com/hc/en-us/articles/360016402332-Bulk-Edit-eBay-Store-Categories-Assigned-to-Shopify-Products