How will the new TOEFL Writing section be scored?

The two tasks are rated from 0 to 5, and the average of these scores is converted to a scaled score of 0 to 30.
Human scorers rate the responses.

Scorers evaluate the integrated writing task on the overall quality of the writing (development, organization, appropriate and precise use of grammar and vocabulary) and the completeness and accuracy of the content. Scorers rate the independent writing essay on the overall quality of the writing:
Development
Organization
Appropriate and precise use of grammar and vocabulary.