Help implementing 'simple pagination' plugin

Hi.

I’ve been trawling through themes and plugins for about a thousand years now just trying to turn my post pagination into big buttons instead of the default ‘easily missed’ text.

I think I’ve found a plugin that will do what I want but I’m having trouble locating the code that I need to replace in order for the plugin to work.

The plugin is: Simple Pagination
My WP site is: http://www.tuckshopmemories.com

The instructions for the plugin say do this:-

Usage for posts

In your theme, open the theme files where you’d like pagination to be used. You need to find calls to next_posts_link() and previous_posts_link() and replace them.

Usually this is the loop.php file.

You would replace those two lines with this:

<?php if(function_exists(‘wp_simple_pagination’)) {
wp_simple_pagination();
} ?>

but I can’t find those files because my theme doesn’t have a loop.php file.

Help?