How do you display featured image (thumbnail) on posts page?

How do I display a post’s featured image along with the post’s excerpt on a posts page?

Similar to this: https://theme.files.wordpress.com/2012/01/fc-showcase.png

Here is my webpage: https://goo.gl/GFmhN

I’ve created a custom template to display posts that is categorized in this category only. I only want featured images and excerpts to display on this page only, not on any other page.

Here is the code for my template:

<?php
/**
* Template name: Look Who’s Joined
*
*/

get_header(); ?>
<div id=”container”>
<div id=”content” role=”main”>
<h1 class=”entry-title”><?php the_title(); ?></h1>
<?php query_posts( ‘category_name=looks-whos-joined’ ); ?>
<?php
get_template_part( ‘loop’, ‘category’ );
?>

</div><!– #content –>
</div><!– #container –>

<?php get_sidebar(); ?>
<?php get_footer(); ?>

Thanks