Add Single Post Navigation Links in Genesis

Genesis has a function which is not active (in most themes) that allows post navigation from older to later posts when viewing in single posts view. That function is genesis_prev_next_post_nav and is found in genesis/lib/structure/post.php

So to add the navigation below the post, add a snippet to your themes functions.php,  you can use

add_action( 'genesis_entry_footer', 'genesis_prev_next_post_nav' );

So here the navigation will appear at the footer as we used the hook genesis_entry_footer

To add navigation links to custom post types check out the way to so here.