The Sales Export functionality in the WP e-Commerce Dashboard & Export plugin can be accessed from your WordPress dashboard area. You can find the menu options under the main “Dashboard” item as “Sales Export” as per this screenshot.
This will let you set up a one-off export, choosing whether you want to export order summary, or order line details. You can choose exactly which fields you want to export, and the date range to extract.
Alternatively you can schedule automatic periodic exports using the “Scheduled Sales Export” option. This lets you choose the same options as the one-off export, but lets you choose to have the export run automatically dumped out to a secure filesystem location, or delivered by email.