As a prerequisite to using the API, the documentation assumes you have completed these setup steps.

API setup Description
Set up the basics
Enable the Google Groups service To use the API, the Google Groups service must be enabled.
Set up a Google Developers Console project Use the API Console to manage and view your application's use of the API's traffic data, your team's membership, and authentication. For more information about the API Console, see the API Console help.

Set up a new project in the Google API Console, and activate Groups Migration API service for this project.