http://codex.wordpress.org/Theme_Features
http://codex.wordpress.org/Template_Tags
roots-dev / functions.php - if it is present in the theme you are using, it is automatically loaded during WordPress initialization (both for admin pages and external pages)
http://codex.wordpress.org/Function_Reference/bloginfo
bloginfo( $show );
// Displays your blog's title
<h1><?php bloginfo('name'); ?></h1>
// Displays the tagline of your blog as set in Settings > General.
<p><?php bloginfo('description'); ?> </p>