Hello and welcome to the Community, Scott. We don't have any direct guidance on setting up eBay in QuickBooks Self-Employed with it being a third-party connection.
When transactions are downloaded in QB SE, you need to categorise them using one of the pre-set categories. These categories are designed in line with HMRC and match with specific lines on your Self Assessment.
You can then run reports, such as the Profit and Loss, to see total values for each category in a specified period. For further information, see our guide on how to Categorise transactions in QuickBooks Self-Employed.
Thanks for reaching Intuit support. We're just a post away if you have further questions or require additional assistance.