Linux

Have you tried setting a breakpoint and seeing if it hits? Assuming the app you are debugging is just a Console.WriteLine("Hello World"); and no breakpoints are set, the app will execute, output hello world, and terminate. Which means you wouldn't see anything happen in VS Code.

If you are super new to all this, I would suggest you look for videos/articles on how to debug using visual studio code as they may provide some insights or concepts you may not already know.

If you get "hello world" after dotnet run your compiler and toolchain were installed correctly.

Make sure you open the right console when debugging C# command line applications (there's a console for debug output and there's a console for terminal output).

Without a screenshot or screen recording I can't tell you exactly what you're doing wrong, but I believe you may be misunderstanding the UI in some way.

Check out Microsoft's guide if you're stuck: https://code.visualstudio.com/docs/csharp/debugging

Omnisharp was a pain to get working properly.

Make sure you install the C# Dev Kit extension, the C# extension alone won't do it.

It's been a hot minute since I've used vscode, but you want to invoke the command pallet (Ctrl+P I think) and create a build profile/task/something. You then want to do the same for a debug profile. This will create two files under .vscode - you will need to edit the debug one to add the build task as a dependency for the debug profile.

You could also try running dotnet build in the terminal before doing what you are doing already.

Also vscodium won't work, the debugging plugin is closed source and is only available for vscode.