Hello, you don’t need to add the HTML, the only file you need to add is the Javascript.
1) Download the latest version of Porto.
2) Unzip all files under a localhost folder.
3) Open the file index-classic.html
4) Add the script right there:

5) Open the server URL: http://localhost/HTML/index-classic.html (or where you have it running).
6) The result will be:

I just tested the exact steps here and it worked that way.
If the problem persists, do that and upload to a server and send me the URL of your site. (not google drive).
Again the style switcher is not required to run your website style, it’s just to generate the skin file, the same you can get from our preview site.
Regards.