If you are using a widgetized home page, you can change the default main content schema setting on the home page of a Genesis Framework child theme by adding the following snippet to your child theme’s function file. Change “http://schema.org/Blog” in the code snippet below to a valid item type of your choice. See http://schema.org for details.

To change schema settings on pages, posts or custom post types, you might consider using the Microdata Manager plugin for Genesis available at the official WordPress Plugin Repository.