Very Simple Google Analytics Tracking is the easiest to use plugin to attach GA tracking code to all pages of your website.
Plugin attaches a Google Analytics tracking code to the of every page, by hooking to wp_head.
Simply enter tracking ID on the plugin settings page: Settings->Very Simple Google Analytics Tracking.
- Upload the plugin folder to the '/wp-content/plugins/' directory
- Activate the plugin through the 'Plugins' menu in WordPress
- The plugin settings can be accessed via the 'Settings' menu in the administration area
After installation check if the plugin works properly by logging in to your GA account (select unfiltered view or segment), visit your site and see if the visit was accounted in GA.