Confusion with TypeScript in Visual Studio

Trying to integrate Cesium with ASP.NET project in Visual Studio with using TypeScript.
I’ve downloaded and added the package to the wwwroot in the project, but seems like the d.ts file is present in Build and the Source, but it always refer the Source. Which I am supposed to use - the Build or the Source in a VS ASP.NET project and which files I am supposed to refer to the project ?

I think both are identical - the only reason you would need to use the one in the Source is if you were changing CesiumJS’s source code and wanted to see the changes reflected as you work.

I am really confused, and I did about 200 tests ( or moe… ) in the past 5-6 days, and none worked.
I am really desperate about working sample with TypeScript.

Have you successfully used any other TypeScript libraries in your codebase? It should work the same way.

What errors are you getting?

It keep blasting me with a various error, in the different setups.
the most common which I am seeing is that “cesium” is not found or “Relative references must start with either “/”, “./”, or “…/”.” alikes. That’s why I were asking for a minimum working example based on TypeScript, since I can stop wondering and just go with it.
At this point i am even not sure if i should or i should not have tsconfig.json. nor i am sure if i need node.js or i dont… etc…
Probably this is absurdly basic questions, but I am beginner in TS, but it would really simplify the work with the .NET environment of Blazor.

PS. I can provide the full source of the project for a test purposes. But it’s a basic one anyway.