How to install csharp mode in emacs

Hi,

I am using emacs 25.3 in Windows 10.
I added this to top of my .emacs file:
(require 'package) ;; You might already have this line
(add-to-list 'package-archives
      '("melpa-stable" . "https://stable.melpa.org/packages/") t)
(package-initialize)

And then I start emacs, per
https://github.com/josteink/csharp-mode
When I do  'M-x package-install<RET>csharp-mode.', I get message 'no
package found'.

Can you please tell me how can I fix it?

Thank you.