There is not particularly much you can do with a Visual Studio solution (.sln), a VC# project (.csproj) and source files (.cs)... As Jesper Juhl said, you need to compile them. I'm not sure, but I assume the source files are already added to the Visual Studio project, so it might be possible that all you need to do is to hit the "Build" button.
Instead of waiting a whole day for an answer and pushing the topic, you could at least try the basic approaches... a large part of programming is own research and experimenting