Drupal For Dummies?

Hi everyone,
I am just starting with Drupal 8 (about 3 days ago). Hosted on siteground.com and am using Windows 10. I took a Java class in college about 4 years ago, so I get the gist of code. But, still, this has a steep learning curve. I really think it will be worth it though to build a website for my new business. I am determined! Is there a resource that is something like "drupal for dummies"?

I've learned modules, adding pages and content, templates and the more basic things. I use the Drupal documentation. Sometimes though, I run into problems and when I look up the solution and is says something that refers to the directory and that kind of stuff kind of goes over my head.

I'd also like to learn how to alter css. I am a beginner, but I have done it in the past and I kind of remember it. Is there a basic resource for this?

Mostly, I get really nervous to add or change anything (especially to the directory) for fear it will mess the whole thing up.

Also, a more specific question, I'm trying to learn to use learn View Slideshow. I found this really great resource https://www.ostraining.com/blog/drupal/drupal-8-slideshows/ . I've added the two basic modules. But it goes over my head when it says "Upload the files to the /libraries/ folder in the root of your site." First, I assume that's referring to cPanel, so I navigate to "File Manager". The dialogue opens and I have all of those choices. Which directory are the instructions referring to? ... "Web Root (public_html/www)", "Public FTP Root (public_ftp)", or "Document root for: website"? And, do I need to create a libraries folder or should it be there already? I don't want to put the file in the wrong place and mess it up.

This was a really large post, I didn't intend it to be when I started out!
Thanks in advance!
Lindsey