Running a Joomla! powered website and want to add Google Ads to earn from advertising? Here's how to add Google Ads to your Joomla site:

1. Set up a Google Adsense account and log in to AdSense.
2. In Google Adsense go to My Ads -> Ad units -> + New ad unit to set up a new ad that will be displayed on your Joomla site.
3. When the ad has been created, click on Get Code to get the HTML script that will display Google Ads on your Joomla webpage.
4. Insert the Google AdSense code to your website's HTML (template index.php) or create a module to display the script (ads) in your desired position. *

* To be able to save HTML <script> </script> in a module  (without code cleanup) you can use a custom code module for Joomla. By default Joomla cleans up the Google AdSense code upon saving so the ads will not display.

You can browse Joomla custom code modules on Joomla Extensions, I can say that Custom HTML Advanced does the job very well.