I think you explained it fine. There's just a huge gap between your explanation and my ability to understand it --- no fault of yours.
You asked: "Why did you added #facebook.com ?"
Well, I added Facebook during the installation process a week or so ago because I was asked if I have any social media that I'd like to link and, since I have a Facebook page, I thought it should go there. It was the same for Instagram, Twitter etc...
As far as I know, I haven't touched any of that original HTML code since it was working two days ago. All I tried to do was add a new link at the bottom of that HTML for my Patreon page. But I don't think I touched that original HTML.
Well that was the first thing I did. I tried to add a Patreon link at the bottom of my working HTML and it didn't produce the result that I wanted so I deleted it. But now the rest of the social media links, which were working, aren't anymore.