Customizing Twenty Twenty Four with Spectra

I'm pretty new to this and learning to build websites through trial and error. I thought I had the basics down and was ready to create my own site. BIG MISTAKE.

I created a child theme of Twenty Twenty Four.
I started making custom templates and a header and footer in the editor (Appearance > Editor).
I set a background color to orange, but when I use a template to insert a page, it doesn't show the background color I chose.
I created custom blocks with orange top and bottom borders, but when I insert them and view the page, the borders are black.
Any suggestions or solutions? I thought I was ready and had a basic understanding, but now I’m completely lost and don't know where to start over.