To install a plugin you generally just need to put the plugin file into your wordpress admin files wp-content/plugins directory. Plugins are tools which provide additional functionality to your application. Once a plugin is installed you may activate it or deactivate it from the Plugins menu in your Wordpress administration area.
Normally the Plugin installation is a simple process. In most cases it is enough to upload the plugin under the wordpress admin files wp-content/plugins directory for the WordPress installation and activate it from the admin panel.
In WordPress 2.8 and in all latest version you can install plugins directly from the admin area. Downlod the plugin from plugin website to your pc, then sign in to your WP admin area and go to Plugins Add New. Browse to the plugin archive and select plugin. Then click on Install button Now and the plugin will be installed easily.