In a WordPress template, if you need to show listing of child pages of a parent page, you can use following code. the first block is the query arguments. Place this code at the top of your template.
$args = array( 'post_type' => 'page', 'posts_per_page' => -1, 'post_parent' => $post->ID, 'order' => 'ASC', 'orderby' => 'post_name' ); $parent = new WP_Query( $args );
Now the sub-pages are in the $parent. Now you just have to print it using the following code block wherever you need to list them in the template.
Make sure you place both of these blocks inside the php tags.
Hope that helps!