where do arguments go this get post code???

i have the following code in my index.php page which gets the most recent posts shows it on the homepage of this site:https://poolplayersforhire.com/wordpress/

<h2>Newest Member</h2>
<br />
<?php $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
query_posts($query_string.'&posts_per_page=1&paged='.$paged); ?>

<?php if (have_posts()) : ?><?php while (have_posts()) : the_post(); ?>

<div class="post">
<h2><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title(); ?>"><?php the_title(); ?></a></h2>
<div class="contenttext">
<?php the_content(''); ?>
</div>

</div>

<?php endwhile; ?>

however, i’m much more familiar with typical get_posts code, not what’s above. to make a long story short, where do i put the arguments to limit which specific category this code gets the post from???