You can observe all Products added to M2E Pro Listings or added as a 3rd Party Listing in Amazon Integration > Listings > Search.
Use the filters to find the product you want to manage. If ASIN/ISBN is available, clicking it will take you to the listing on Amazon. Clicking the
icon in the Manage column will take you to the M2E Pro Listing's products page, where you will be able to manage its settings.