I discovered how to select new pages (for example, countries, scenes, technologies, etc.) but I'm not a premium user, so I can't use them. Now that I've selected them, I can't figure out how to unselect them. Is there any way to do so?
You Go to the same page as you do to select them then click the slider of the page that you want to deselect.
I've done that before too. You just click Customize pages again then there should be an option which will let u un select them.
I can't find where customize pages is
It's on your left, under neath items.
What if the customize pages icon isn't appearing?
You can also get to that page by clicking "Enable Premium Pages" on your account billing page (from the dropdown in the top right of any page) or by navigating directly to https://www.notebook.ai/customization/content_types