The Workshop module was rarely used in previous versions of Moodle due to its cluttered design and high level of complexity. That said, the redevelopment of this peer assessment module has been worth the wait as it now offers a much more user-friendly interface.
You can have three elements to your workshop:
Use examples: Students are provided with sample items that they can practice evaluating either before they send in their work or before they review others.
Use peer assessment: The "traditional" use of the workshop where students' work is distributed amongst them for them to evaluate.
Use self-assessment: Students reflect on and evaluate their own work
Grades are given for submission (the mark the students will get for their submission) and for assessment (their mark for evaluating the submissions of peers)
Grading strategy options include Accumulative grading, Comments, Number of errors, and Rubric set out.