When you make a page, you set the page template with the editor’s setting for templates (found on the right sidebar area). The same for changing an existing page layout, you would open it in the editor, then change the template setting from the drop down list.
Hi Dorothy… for the blog, this requires special coding to achieve that, but unfortunately this theme does not have that layout as an option, only a left and right. I could consider that as an added feature in the next update for the theme.
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