Include custom post type in Wordpress loop

Sorry, I think I read every post about this but cant get it to work.

I have a Wordpress custom post typ called "external" and I would like to show both the post from "external" aswell as my normal standard posts at the same time on my homepage.

This is my loop:

<?php 
get_header(); 

if ( get_query_var('paged') ) { $paged = get_query_var('paged'); }
elseif ( get_query_var('page') ) { $paged = get_query_var('page'); }
else { $paged = 1; }?>


<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
<div id="post-<?php the_ID(); ?>" <?php post_class(''); ?>>
    <?php the_content(); ?>
</div>
<?php endwhile; wp_reset_postdata(); endif; ?>    

How can I include the "external" posts in this code?

Thanks!