Extract the wpcompresshtml.php file and upload to the '/wp-content/plugins/' directory.
Activate the plugin through the 'Plugins' menu in WordPress.
If there are areas which you do NOT want compression to be applied, simply enclose each area with a pair of <!--wp-compress-html--> tags. Drop in a <!--wp-compress-html no compression--> tag within each area marked in this way to tell the plugin that area is not to be compressed. Don't worry - these configuration tags will be stripped out by the plugin.