Well...not EVERYTHING. - This part's okay.
The thing of it is...
When you don't know anything...you REALLY don't know anything.
If you add a page, and it somehow ends up as a subpage under the wrong main page... just drag it under the correct main page. (Hit the "Pages" link to get the lineup: Insert / Pages / Themes)
That's it.
.....
Oh, be sure you hit [Publish] afterwards or it won't take.
Embarrassing, but #### happens.
When I published one of my pages, I didn't notice how it was lined up as far as the home page was concerned, so...
Adding More Pages to Website
https://www.seostuff123.com/adding-more-pages-to-website
WHAT THE...
Went to page's 3-Dot menu.
Clicked "Properties".
Clicked "Advanced".
Custom path:
Current Link
https://www.seostuff123.com/adding-more-pages-to-website
Entered: https://www.seostuff123.com/home/adding-more-pages-to-website
Message: "Invalid path"
Then entered the following:
www.seostuff123.com/home/adding-more-pages-to-website -> "Invalid"
seostuff123.com/home/adding-more-pages-to-website -> "Invalid"
/home/adding-more-pages-to-website -> "Invalid"
home/adding-more-pages-to-website -> "Invalid"
/adding-more-pages-to-website -> "Invalid"
adding-more-pages-to-website -> It was fine with this one.
SO...
If you didn't copy and paste the contents of your page from a file... Copy the content now and paste to onto a text document. - It's nice to have a backup. - You never know.
Go to page's 3-Dot menu.
Click "Delete".
Go back to the home page's 3-Dot menu.
Click "Add subpage".
Name page and paste contents onto it.
BEFORE CLICKING THE <PUBLISH> BUTTON, CLICK PAGES (from Insert/ Pages / Themes selection under the <Publish> button).
MAKE SURE THE PAGE YOU'RE ABOUT TO PUBLISH IS WHERE IT'S SUPPOSED TO BE!!!
In other words, if a page is supposed to be a subpage of your home page, IT NEEDS TO BE UNDER THE HOME PAGE, NOT ON TOP OF IT!
So... if the about to be published subpage is under the home page...
Click <Publish>.
Click link icon to make sure all is well.
https://www.seostuff123.com/home/adding-more-pages-to-website
All is well.