you can use this code to list posts from category:
<ul>
<?php
$args = array( 'numberposts' => 10, 'category' => 1 );
$postslist = get_posts( $args );
foreach ($postslist as $post) : setup_postdata($post); ?>
<li>
<a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
</li>
<?php endforeach; ?>
</ul>
duplicate and use for categories…
and where shall i put it? how can i use code in the menu section? sorry, quite a newbie 😀