Steps:
- Create Content type in your Drupal 8 instance
- Map the fields of the content type to the JSON data in src/Form/BaseUrlForm.php (starting on line 108)
- Save changes and install the module
- Navigate to the form '/admin/config/baseurl' and paste in the json endpoint
- Submit
Original attribution: http://jordanpagewhite.github.io/drupal-8-json-to-nodes/