You must use the Ebay Documentation! No one will do this job for you and the response rate in the ebay dev forum ist near by zero. Here you see a complete overview over all calls provided by the TradingAPI. Es of them has a very good description and documentation. Use STRG + F in your browser to search for specific fields or information. In this case you can make a GetOrders call to retrieve most of the relevant items. Than make a GetItem call on the item of the order. In this response you cab look at [Item].[Seller] to retrieve missing informations about the seller.