Unless otherwise indicated, the code snippets you see below should be placed into your theme’s functions.php file.
Below is the code to customize the add post navigation to Genesis HTML5 (recent) themes:
<?php //* Do NOT include the opening php tag shown above. Copy the code shown below. //* Add post navigation (requires HTML5 theme support) add_action( 'genesis_entry_footer', 'genesis_prev_next_post_nav' );