WordPress.org

After you've downloaded and extracted the files:

1. Upload the complete WP-Slimbox2 folder to the /wp-content/plugins/ directory
   
2. Activate the plugin through the 'Plugins' menu in WordPress
   
3. Visit the "WP-Slimbox2" page in your WordPress options menu to configure any advanced settings.
   
4. Manually add the rel="lightbox" attribute to any link tag to activate the lightbox or rel="lightbox-imagesetname" for an image set, using the title attribute to store a caption. Alternatively you may use the autoload option to automatically prepare links to images and additionally enable picasaweb and flickr integration to easily utilize their albums.