Missing a "Startup.cs" file for a ASP.NET project in Visual Studio?

In the Learn ASPNET coarse, I am following the 2nd article of the 1st module named " Getting Started with ASPNET and Visual Studio" (https://www.codecademy.com/courses/learn-asp-net/articles/getting-started-with-asp-net-and-visual-studio). The article just basically has you follow a video tutorial on setting up ASPNET Razor Page with Visual Studio. Here is a link to just the video tutorial (https://www.youtube.com/watch?v=eMpWKC8Q0o8&t=334s).

Upon watching the video, I appears like they are using an old version of VS because the UI looks different. However, the main problem that I am running into is that my new TestApp.cs project does not have a Startup.cs file in my Solutions Explorer.

Does anyone know how to set up a new TestApp project with a Startup.cs file?
Is a Startup.cs even necessary?