Product Variants and Attributes

Greetings.  I'm just learning my around around V2.8.  Trying to understand if I can, for example, have a table of product variant "options", say for shoes. Each shoe may come in a size ranging from D7.0, D,7.5, D,8.0,etc.,  E7.0...etc up to about 40 various sizes (width/length) for each shoe.  Then, as I enter a new product, can I specify/select from a check box which size (and quantity in stock) that shoe comes in. Then when the customer orders, have the sizes available (based on in-stock) appear in a drop-down list.  From what I am reading, I would have to enter the product variants for each and every shoe and size options at the product level?  Not sure.  Thanks

You probably want 1 Product with 1 ProductVariant.  That PV has an attribute for Length and another for Width.  Then you use ProductAttributeCombinations to keep inventory on 7D, 8E, etc.

In the Products Template selection the choices are Variants in Grid and Single Product Variant.
In order to display the variants in a drop down, should there not be another template choice for that?
If so, how to enable it?

The goal: have shoe sizes in a drop-down.  Each has a unique SKU. And display under Qty selector.

P.S. As I slowly learn my way around nop I am very impressed with level of sophistication of the architecture.
I'm still at ground zero in learning!

Your product template would be Single Variant because you'll only have one.  You would set the Attributes in the ProductVariant itself.

Here's an example from the demo: http://demo.nopcommerce.com/etnies-mens-digit-sneaker

There is 1 Product with 1 ProductVariant and that PV has 2 Attributes (Size and Color).  You can set AttributeCombinations which would track inventory (we have 500 Green Size 8's, 250 Red Size 9's, etc).