You can either use the automatic plugin installer or your FTP program to upload it to your wp-content/plugins directory the top-level folder. Don't just upload all the php files and put them in /wp-content/plugins/.
Activate the plugin through the 'Plugins' menu in WordPress
Insert shortcode by click WP AD Gallery button on post editor and follow the options
Requires: 3.0 or higher Compatible up to: 3.4.2 Last Updated: 2012-6-18 Downloads: 9,061