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
set up widget
Requires: 2.9 or higher Compatible up to: 3.3.4 Last Updated: 2013-6-20 Active Installs:
Less than 10