Locate the head.phtml in the folder view of your Magento Installation.
It should be located at
Copy Text United snippet code from a website translation project details page and paste it above the closing </head>
* Template for Mage_Page_Block_Html
<!DOCTYPE html PUBLIC "-//W3C//DID XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1>
<?php echo $this->getChildHtml('head') ?>
--PASTE THE SCRIPT HERE--
Save the changes.
In order for the translated version of your website to appear on-line, you'll have to publish translations in Text United. Open the overlay editor using the PREVIEW button in the upper right corner.
Click Publish icon from the menu and click Publish translations button in the dialog window.
After translations are published, visitors can access the translated version of your website using a language selector.