To upgrade to Joomla 2.5.2:
- Log into your Joomla Dashboard
- Find and click the icon labeled Joomla 2.5.2 Update Now!
- Put a check in the box next to the Joomla update file (see screenshot below) and click Update in the top right menu
- When the update has completed, you will see a success message similar to Updating file was successful. You will also see the version number at the bottom of the page update to Joomla 2.5.2 (refer to the screenshot below)