Although each product is distinctly defined on the back end with its unique field settings (price, title, SKU, image, etc.) it is not visible anywhere on the front end of the website as a mere product. In Ubercart you inputted the product information in the same place that you controlled the product display.
But Drupal Commerce has decoupled the product itself from the product display. This give us a lot more flexibility because a conference registration or meal or membership does not necessarily need its own display page. By decoupling the product from the display, we can combine them in a single display, linking them up together in new combinations.
So next we create a content type that is a Product Display. These products could be displayed in Views, perhaps other ways, but in my case, I'm using a node to display these products.
What makes this node a product display node is the "product reference field" that we see has been added to this content type.
On this new Membership Product Display content type we will use this product reference field to connect the product display to the membership product. For the Conference Product Display, we will use three product reference fields to link it to all three kinds of products: membership, conference participation, and conference meals.
Notice that these products would have no presentation on the website without these product display nodes. And because we can reference different product types in our display node, we can combine all three product types in the one display node as we do in the Conference Product Display.