treffer on "Help Adjust Walker"

Found this code

class Example_Page_Walker extends Walker_Page {
function start_el(&$output, $page, $depth, $args, $current_page) {
$output .= '<span class="move">\</span>';
parent::start_el($output, $page, $depth, $args, $current_page);
}
}

$example_walker = new Example_Page_Walker();
wp_list_pages(array('title_li'=>'', 'depth'=>1, 'walker' => $example_walker));

How do I change it so the the span is inside the li tags of the wp_list_pages output?

Where do I put these pieces of code?

Functions.php and where mu menu outputs?