Once you have a instance of Docker\Docker you can get one the Docker\Manager\*Manager to call the API.

use Docker\Docker;

$docker = new Docker();
$containers = $docker->getContainerManager()->findAll();

There is 6 different manager:

• ContainerManager: Handle calls against containers (find, create, attach, pause, ...)
• ImageManager: Calls for image (find, build, create, commit, ...)
• ExecManager: Manage exec process in a container (create, start, kill, ...)
• VolumeManager: Manage docker volumes (create, remove, find, ...)
• NetworkManager: Manage docker network (create, remove, find, ...)
• MiscManager: All other calls not corresponding to a previous Manager (authentication, version, events, ...)

You can check the [reference documentation](@TODO PHPDOC) for a list of all methods of each manager.