coding changes for avatars

[mikewilltoo]

Sorry to be such a pest with questions. Once I get over the hump with this theme they'll stop. Anyway,

I'm trying to get avatars to appear in posts (and eventually, comments). I thought it wouldn't be all that complicated. I'm trying a plugin, add-local-avatar. Installs OK. Avatars uploaded. Now the coding. The relevant instructions are:

Put this code in your template files where you want avatars to appear:

<?php echo get_avatar(); ?>

The function takes the following parameters:

1. Identifier; A blog user ID, an e-mail address, or a comment object from a WordPress comment loop (for comments).
2. Size (pixels); defaulted to value set above.
3. Default image if no Global (public) or Local (private) avatar found; defaulted to value set above.

Apply format to the avatars with something like the following in your style.css theme file:

* For comment avatars, .avatar { float: left; padding: 2px; margin: 0; border: 1px solid #ddd; background: white; }
* For avatars in post content, .post_avatar { padding: 2px; margin: 0; border: 1px solid #ddd; background: white; }

Examples for your theme's template files:

* In single.php declare <?php global $post; ?> if not already declared and then use <?php get_avatar($post->post_author); ?> to show the post author's avatar.
* Inside the comment loop of comments.php use <?php get_avatar($comment); ?> to show the comment author's avatar.

I inserted the code <?php get_avatar($post->post_author); ?> in page_blog.php after the breadcrumb and ahead of the title, but that, or that by itself, did nothing.

I also can't make out where exactly to put the formatting in style.css.

I'd appreciate any suggestions. This looks like pretty serious coding, certainly over my head (although I can follow instructions), so if the response is "leave it to the pros" I understand. THANKS.