Multiple Post Thumbnails Plugin – Need help with code

Here is a complete example using the code you provided:

For your functions.php file:

<?php
// Add secondary thumbnail (featured image) in posts */
if (class_exists('MultiPostThumbnails')) { 
 new MultiPostThumbnails(array ( 
   'label' => 'Secondary Image', 
   'id' => 'secondary-image', 
   'post_type' => 'post' )
   );
  new MultiPostThumbnails(array(
   'label' => 'Quaternary Image',
   'id' => 'quaternary-image', )
   );
  new MultiPostThumbnails(array(
   'label' => 'Tertiary Image',
   'id' => 'tertiary-image', )
   );
 }
add_image_size('post-secondary-image-thumbnail', 176, 58, true);
add_image_size('post-tertiary-image-thumbnail', 176, 58, true);
add_image_size('post-quaternary-image-thumbnail', 176, 58, true);
?>

And for your page template:

<?php
/*
Template Name: Home
*/
?>
<?php get_header(); ?>
<div id='main-content'>
<h2>What We Do</h2>
  <ul id="we-do">
    <?php 
      query_posts("posts_per_page=1&post_type=page&page_id=168");
      the_post (); ?>
    <!--If you want to refer to the child of parent page, use "post_parent=" -->
    <li>
      <h3><?php the_title(); ?></h3>
        <?php the_excerpt(); ?>
      <?php 
        MultiPostThumbnails::the_post_thumbnail('post', 'secondary-image', NULL,  'post-secondary-image-thumbnail');
      ?>
      <a href="https://wordpress.stackexchange.com/questions/35258/<?php the_permalink(); ?>" class="button">View More</a>
    </li>
    <?php 
      query_posts("posts_per_page=1&post_type=page&page_id=236"); 
      the_post(); 
      ?>
      <li>
        <h3><?php the_title(); ?></h3>
        <p><?php the_excerpt(); ?></p>
      <?php 
        MultiPostThumbnails::the_post_thumbnail('post', 'quaternary-image', NULL,  'post-quaternary-image-thumbnail');
        ?>
        <a href="https://wordpress.stackexchange.com/questions/35258/<?php the_permalink(); ?>" class="button">View More</a>
      </li>
    <?php query_posts("posts_per_page=1&post_type=page&page_id=240"); the_post(); ?>
    <li>
    <h3><?php the_title(); ?></h3>
    <?php the_excerpt(); ?>
    <?php 
      MultiPostThumbnails::the_post_thumbnail('post', 'tertiary-image', NULL,  'post-tertiary-image-thumbnail');
      ?>
    <a href="https://wordpress.stackexchange.com/questions/35258/<?php the_permalink(); ?>" class="button">View More</a>
    </li>
  </ul>
</div><!--END main-content-->
<?php get_sidebar(); ?>
<?php get_footer(); ?>