//you have to open the homePage.php file and on line 55 you have to replace this line:

 <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>

//with this one:

 <h2><a href="<?php echo(get_post_meta($post->ID, 'link', true)); ?>"><?php the_title(); ?></a></h2>