Thankyou for creating Opigno. It is really great App. I am trying to customize opigno so that i could sell Course with different Attribute. For example: My Course title will be Business English Attribute must be able to select by the client before they add to cart are. Start date: (in select list) -- with the attributes -- : June 6 - August 1st, September 3rd - October 22nd, October 29th - December 19th. You can see this example similar to Selling Shirt with different Size Attribute or different Color Attribute in Cloths Store. To make it work for me. I did the same process for displaying Selectable Attribute that we do during setup ecommerce site i.e Taxonomy. and adding Product Reference field in Class in Manage Field Section. It display the course as i expected but my problem begin when i knew that buying the Course is not now displaying the course in My Course Section of the Student. And the products which used to create by default like product-og-5 are not creating when creating Course or Class.