You could see on Homepage Layout manager page that we have 15 clean page boxes. These “Clean pages” are actually the pages you can create under the Pages -> Add New menu on the left side. We’ve created 15 of these blocks in case you don’t want to use any of the custom blocks (about, services,…) we’ve created.
So if you’ve added any clean page box to your homepage layout, you first need to go to Pages -> Add New to create a new page. After you’ve created it and added all the content you want, go to Appearance -> Theme Options -> Clean Pages Settings and select the page you’ve created for the clean page box you’ve added on your homepage layout manager.