Please check out my website austinhigh1961.com and see how ugly it is.
I don't understand how to correct it.

Mickey,

This is very simple to fix.

Under Admin Functions, click on Change Design. In the first box, which addresses Professional Designs, Themed Designs, and Advanced Designs, at the bottom you'll see Page Alignment. Change it from Left to Center and you'll center the content on the page. Be sure to click SAVE ALL CHANGES. If you don't like the way it looks, you can go back to aligning the content on the Left.

Did you mean the left oriented page OR the all white background that blends the right page edge?

Scott showed how to change the left thing. To change the white background and make the page more delineated, change the background color. I don't have the older style so not sure where that is on Customize Design, just that it is there. Scott's page shows how that then looks.

You can also upload an image for a background. Be careful though since it should be one that "tiles" well for everyone. Many backgrounds do not work well when tiled and can look distracting.

All this is very personal preference including the next.

I recommend going to the newer design though (Change Design) and pick Responsive. Our site is "Responsive". Has more choices so a bit harder to set up because of the variations possible.

As an aside, phones and tablets typically do not have room to show an image. Ours is just a black background to make it easy on the eyes if one does have a large screen.

The biggest advantage for the change is that it will work way better for PHONE screens. Many users even in our year now use their phones. Our is about 25% now.

Regarding Jack's suggestion, to change the background color from white to something else, under Admin Functions, click on Change Design. Then, scroll down to the Site Colors box and change the Background Color. Click SAVE ALL CHANGES.

You may also wish to make your vertical scrollbar on the right side more visible. Here's how: under Admin Functions, click on Change Design. In the Site Color box, check the "Use default scrollbar, do not color." Click SAVE ALL CHANGES. This will give you a gray scrollbar in a white scrollbox. You'll see this scrollbar if you look at Jack's site or my site.

Jack,
Why is your site narrow with black edges and mine is full width?
Jim

This is the one I am talking about, not the one on the left:

www.ephs61.com

In Customize Design I have "Fixed" and you have "Full"

Full (IMO) is way too wide for comfortable reading on a 1920 wide PC screen for CC type content. A 4k screen is even worse. I had that for a bit and hated it real quick since most sites are awful. Great for gaming and 4k videos and images though.

Usually what is done is to split content up into columns or some other way to break up long strings of text.

For example, Craiglist uses one format to show many images and then reverts to a smaller view for the details. Newspapers do the same thing (also done in print).

Content is the key here on what works and what doesn't.

The screen used to preview (a smaller res screen will not reveal the huge space there) and ones own preferences.

As you probably realize, it is easy to switch back and forth for your sites to see what they look like. That's then nice thing about responsive - assuming the content has been coded to be responsive. [Something that CC needs to have some lesson material published.]