To add a WordPress Plugin using the built-in plugin installer:
Go to Plugins > Add New.
Find the WordPress Plugin you wish to install.(select the .zip file)
Click Install Now to install the WordPress Plugin.
The resulting installation screen will list the installation as successful or note any problems during the install.
If successful, click Activate Plugin to activate it, or Return to Plugin Installer for further actions.
If you need some other help please let us know.