Paul Jones has a quick post covering the use of his Atlas.Orm package in a Symfony application, showing how to easily integrate the two.

Are you using Symfony 4? Do you want to use Atlas with it? We now have a Symfony bundle and Flex recipe that makes installation and integration a breeze. Two commands and one .env file edit, and you’re ready to go.

He includes the commands you'll need to get it installed and generate the skeleton mapper files from your database. Symfony then automatically injects the Atlas instance from the container (code example included). He ends the post linking to other resources about defining relationships, managing transactions and handling events with the Atlas.Orm package.