Like most content management systems, PyroCMS uses front-end themes. Though PyroCMS themes are built a bit differently than what you might be used to from other systems, they're still quite easy to create. They're so easy, in fact, that very little PHP experience is required to assemble them!
He walks through things like the folder structure of the templates directory and how to get started on a custom "Foo" theme of your own. He covers how to lay out the HTML markup for the theme and how you can use partials for the sections of the site. He briefly touches on using multiple layout files and how to use different layouts shown only to mobile devices.