Having problems creating layout.cshtml in Visual Studio 2017

Having problems creating layout.cshtml in Visual Studio 2017

I've found tons of great examples of Jquery Mobile applicable to Visual Studio developers - all using older Visual Studio MVC templates i.e. they have the App_Start folder, use bundling, etc. where the 2017 Visual Studio/MVC has done away with both of those constructs.

 ALL i want to is create my first simple test app using jquery mobile (single listview control). I can cut/paste code via notepad into an HTML file, double click it,  and it displays exactly as expected.  But I have not been able to replicate that in MVC 5.  That "same" code has none of the mobile styling queues.  I've been developing web pages for over 20 years but new to MVC.  

Any help is appreciated. 
This is all done trying to create an ASP.NET Core 2.2 MVC app using C#.

Thank you in advance