You can observe all Products added to M2E Pro Listings in Amazon Integration > Search or Amazon Integration > Listings > Items > All Items.

In the All Items grid, you can use the filters to find the product you want to manage. If an Amazon Item ID is available, clicking it will take you to the listing on Amazon. Clicking the arrow 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.