To enable Dynamic Regions and PHP Regions add the following lines to your config.php file.
define('DYNAMIC_REGIONS', true);
define('PHP_REGIONS', true);
After that is complete, you may now add PHP regions to your page styles (i.e. <?php example ?>). You may also create dynamic regions in the design tab and add them to your page styles (i.e. <dregion>example</dregion>).
Please note that you should not include the opening <?php tag and closing ?> tag in your dynamic regions.