Hi Spyros,
Please use this <?php the_excerpt(); ?> below <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
Final result will be like this.
<a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
<p><?php the_excerpt(); ?></p>// Kept p tags here for spacing only. You can choose your own elements for styling.