With this plugin you can control the text which will be shown as description on the search engine results pages.
There are several ways to install a plugin in WordPress. For newbies this way is highly recommended:
wp-meta-description.zipfrom 'Install Plugins'
For correct working make sure that your site visibility isn't blocked. You can find this option under 'Privacy' in 'Settings' menu. Prevent to intall more than one plugin for the same task. Prevent double entries in the header and values which are in conflict to each other.