C# FFmpeg Dynamic-Link Library

I need FFmpeg as dll for C#. I want to do something like;

static void Convert(Stream onlyAudioStream, Stream onlyVideoStream, string path)
{
    FFmpegNameSpace.FFmpeg ff = new FFmpegNameSpace.FFmpeg();
    ff.AddInput(onlyAudioStream);
    ff.AddInput(onlyVideoStream);
    ff.Save(path);
}

And the problem is I don't know how can i get ffmpeg dll.

Example: I did this before in libwebp. Things we need to do to get libwebp dll; 1- Download libwebp source 2- Open Visual Studio 2019 Developer Tools 3- Run command in libwebp source directory "nmake /f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output" 4- Done you will find dll in output directory

Edit: I searched a lot and couldn't find the solution. I decided to use ffmpeg.exe whenever I need it. Thank you all