First and always, make sure to confer with your department administrator regarding internal deadlines and processes that assist you in meeting campus requirements.
There are two parts to completing the required Annual Performance Review (APR).
PART ONE: Meet with the postdoc.
You may use whatever evaluation tool your department may have developed, or one that suits your purposes to arrive at the proper rating for performance. Discuss openly so that the rationale for the rating is understood by the postdoc.
PART TWO: Complete the on-line Annual Performance Review form for postdocs.
What is required by UCD's Postdoctoral Policy is to file annually a "public record" of a performance rating with the Postdoctoral Office. It also has a section for updating the postdoc's annual salary for the upcoming fiscal year (this is not required).
This is what the form looks like (mostly), but it is now electronic: 2013 POSTDOC Annual Performance Rating Sheet - Copy.doc
This is the detailed process: Evaluation process at UC Denver
Also useful might be these items:
NPA Core-Competencies.pdf NPA Competency-Checklist.pdf