An employee handbook is one of the most important communication tools you can have between your company and your employees. You may complete an on-line application at the Contra Costa Human Resources Department at 651 Pine St., 2nd Floor, Martinez, CA 94553.CalChamber's Employee Handbook Creator online tool takes the guesswork out of creating a California employee handbook. Learn the benefits of having an employee handbook, what information you should include for employees, and find easytouse templates. HR Hotline Call 1-888-599-7645. This handbook is an instruction manual intended for employers only. The mission of the Contra Costa Community College District. (4CD) is to empower all students to fulfill their educational and.