Once you pick a theme, you go to a detailed page that gives you the rundown on what makes that theme tick.
Every major feature got its own section.
The preview window gives you a live preview of the theme, including a mobile one.
The featured homepage. Browsable by type or theme.
The featured detail view gives you a live preview of the site and the url to the original portfolio. Plus, a button to get you started with that particular theme.
To get a picture of the overall marketing site, please have a look at the Marketing Sitemap (PDF)