Under your Genesis Menu select Theme Settings.
You can select the default layout of your site on this page, the demo uses content/sidebar.
note: You can adjust the layout for each post and page on their individual editing screens, this will just be the default layout for all pages unless you change them.
Scroll down to the Content Archives area of this page and configure the following settings.
Display: Entry Content
Limit Content to: 500 characters
Featured Image: Include
Featured Image Size: Vertical Image 350×438
Image Alignment: Left
You can also configure other various settings on this page, including adding your Google Adsense code.