The Use Custom Docker Compose File option is available on all Docker Compose build steps and is used to select a compose file other than the default ($WORKSPACE/docker-compose.yml). This option supports both absolute and relative paths.
In the case of the Start service step, use the Scale option to spin up more than one running instance of a service.
Use the Container Index option to select the instance where you want to run the command.
If the Working Directory is left empty, the plugin will use the default one for the container.
Use the Snippet Generator to generate a Docker Compose Build step "metastep" for a scripted pipeline.