There, I finally logged in.
As you can see, I premade a big picture so it recognizes it as a wraparound picture. To the best of my knowledge, the only requirement for CoverCreator to do this is for the picture to be wider than it is tall. If you have a tall picture, you'll tend to get front only options.
But instead of 2 or 4 (my picks for front cover, though #3 is okay too), we're gonna pick 1 and try to blow it up.
On this one, you get a great deal of excess to the picture. It's front-only so the stuff that extends to the binding and back cover does not show up. However, something seems to be wrong as all front cover text is missing. So we're gonna restart, and this time, we'll choose the last option.
In addition to the first design screen, there are three tabs: paint roller, a box thing, and a T. That is, color designs, layout, and text. I switched to this layout. There are advantages to both options but neither is ideal (this is when you would use PDF mode, tbh). Type 1 has a small space for a picture, but the back has a clickable image, allowing you to have a front cover and back cover. Type 2 has a bigger space for the front cover, but no back cover. It also has a butt-ugly pink secondary color. Let's make it all black.
Type 2 turns out to have extra space, so we click on the edge tabs and stretched the picture. Finished result.
But I've decided I don't want a single front page at all, so I'm gonna start over.
Did you know that there's a second page? This time, we're going to click on the full-cover. We've chosen Cinzel Decorative and a kind of silver color to go with our book.
When you're done hit Preview. They'll show the results and you say Save & Submit. This works for everything but Hardcover and foreign language, so unless you want to do something cool (like a collage cover), it's not necessary to use a PDF. The trick is to force the creator to switch to wraparound mode.
If you really must use a PDF, learn to use GIMP well, then have the main cover and the binding as separate layers. That way if the binding is all by 0.33 mm, you can just expand the binding.