I have downloaded and unzipped the latest files for Demo 19, metronic_v8.0.38_html_demo19.zip. I want to enable switching to dark mode via the button in the toolbar at the top of the page. When I open index.html and click on the "dark mode" button. What I get are instructions to run a Gulp command. Lacking gulp, I found instructions on the web for installing node.js and then gulp. I installed node.js and gulp specifically just for the purpose of gaining access to the Dark Mode theme for Demo 19.

When I follow the instructions for installing the dark theme via Gulp, I get the following error:

[06:03:01] Local modules not found in ~\source\repos\Themes\Metronic\metronic_v8.0.38_html_demo19\tools
[06:03:01] Try running: yarn install

Please advise.