CleverAge/ProcessBundle must be installed.
Make sure Composer is installed globally, as explained in the installation chapter of the Composer documentation.
Open a command console, enter your project directory and install it using composer:
composer require cleverage/doctrine-process-bundleRemember to add the following line to config/bundles.php (not required if Symfony Flex is used)
CleverAge\DoctrineProcessBundle\CleverAgeDoctrineProcessBundle::class => ['all' => true],