WordPress.org

1. Define the tooltip, bubble or sweet in line 35
2. Upload all files to the /wp-content/plugins/ directory, include the php-, gif-, css- and the js-file
3. Activate the plugin through the 'Plugins' menu in WordPress
4. [Optional] Edit in line 86 of js/BubbleTooltips.js. You can change the ID of function the tooltip or without ID - example without ID, for the complate site: enableTooltips(); with ID - example with ID content: enableTooltips("content").

See on the official website.