1. You can edit your existing products by visiting your products page. Hit the options toggle button (3 small dots) for the product you wish to edit, and clicking on "Edit" in the drop-down menu.
2. You can also edit your product while viewing its infopage. On the top right click the 3 dots menu and choose the "Edit" option. This will take you to the product editor where you can update or add more details to your product. Do not forget to hit "Save" after you made your changes.