OK here’s how it worked in short form (without links and titles) in case anyone else is wondering:
pasted
<?php add_theme_support('post-thumbnails'); ?>
into the function.php file to turn on the thumbnail function for 2.9
added thumbnails to 3 posts in 3 unique categories (3, 4, 5)
made a style sheet with 3 columns (homeleftcol, homemidcol, homerightcol)
with this code for the homepage template:
<?php get_header(); ?>
<div id="home_content"></div>
<div id="homeleftcol">
<?php query_posts('cat=3&showposts=1'); ?>
<?php while (have_posts()) : the_post(); ?>
<?php the_post_thumbnail(); ?>
<?php endwhile;?>
</div>
<div id="homemidcol">
<?php query_posts('cat=4&showposts=1'); ?>
<?php while (have_posts()) : the_post(); ?>
<?php the_post_thumbnail(); ?>
<?php endwhile;?>
</div>
<div id="homerightcol">
<?php query_posts('cat=5&showposts=1'); ?>
<?php while (have_posts()) : the_post(); ?>
<?php the_post_thumbnail(); ?>
<?php endwhile;?>
<?php get_footer(); ?>
