How do I make a C# Console app build and debug in Visual Studio Code?

This is on a Windows 10 OS Version 22HG2 (OS Build 19045.5371)

How do I make a C# Console app build and debug in Visual Studio Code?

I have already built my C# Console App in Visual Studio Code. The issue I have is when I reopen the folder where the project file is in Visual Studio Code and then rebuilding the code and debugging it again.

Here is what I do and what happens. After I open the folder where the project file resides, I click on this to process the code to debug:

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And then I click on the appearing "Run and Debug" button

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But then the bottom status bar says "Looking for CSS classes in the workspace..." followed by a percentage in paragraphs. Why is this? Why does this happen when there are no CSS classes at all and my project is a C# project?

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Why is this? This is just a brief snapshot of some difficulties I find when I reopen a project after I have closed Visual Studio Code. I have experienced other errors and problems in building and running my code.

To continue, in order to deal with the project as a solution, I click on this icon to open the solution panel.

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This seemingly allows me to view the solution. As the following view appears, I click on the project.cs file and attempt a debugging session from there.

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With this file being displayed, I clicked on the menu option, Run -> Start Debugging

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Then, at this point, in the pop up option window that appears in the middle and top of the development environment, I pick "C#":

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Something went wrong and in the bottom right of my IDE, I get this message:

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Please advise. What should I do now?

There are some websites where I can spend time following steps to set up a proper development environment. Before I spend time doing this, I think I will spend time looking at the a few short tutorials Youtube on this topic. The one I seemed to be the best had a step at the beginning of the tutorial where he typed 'dotnet run' in the terminal window of the IDE. I tried that and I got some wierd results on my project that I thought I would mention here.

First of all, in the status bar at the bottom, it mentioned CSS loading, for some reason, but also a notice that the IDE was initialising MSBuild project tools.
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Then, once that was over, I got this error message:
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Please advise. What should I do now?