In the products section at the top, click on the Bulkupload/edit button
This will take you to the Polytag bulk upload/edit tool, where you will see all of your products you have uploaded so far. You can delete data from cells and type or paste in new data to make edits. You can also drag data from one cell to another, like using Microsoft Excel. You can also add more products too.
The tool will perform basic data validation and will highlight any errors with a red ring around cells
When you're ready, click on the Savechanges button