how to upload an helm file to my website

You would need to use whatever website authoring software you usually use to maintain your website. I'm not sure about what software one uses for a Mac, since I'm a Windows user, but for Windows you would use Front Page, or Expressions, or something like that. Do you do regular maintenance on your website? Does someone else maintain your site? If someone else maintains it, then they would be able to upload the file.

You're welcome. Of course, you would need to have permission to add content to the website to add an html file to it as well, but since you are saying it is your website, I'm guessing you have that access.

Okay!