In addition to the dotnet package, the Vintage Story server also requires screen, so you should have the screen command available on your system.
You should be able to run screen -r on the machine VintagestoryServer is running on; this will bring up the server log, and you can enter commands here as the server. When you are finished, press Ctrl+A, then Ctrl+D on your keyboard to detach from the server process without killing it.