Essentially, you can use it to distribute work on a celery cluster very easily.
You typically want to use of the standard operators BashOperator PythonOperator or the best I think: DockerOperator
Note that communication between dag components happens over Variables or XCOM.
To pass data to the DockerOperator, you read from XCOM or Variables, and set some environment variables for the docker. For reading results back, by default, you get back the last printed line in to the stdout of the docker container.