A family law contempt proceeding in California is initiated by filing and serving FL-140 Order to Show Cause and Affidavit for Contempt, along with an applicable Affidavit of Facts Constituting Contempt (FL-411 or FL-412). These forms and all others in California are available for download at: www.courtinfo.ca.gov/forms/
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
In addition to what Brian has said, the court's self help center can give you the forms and tell you how to fill them out, file and serve them. Check at your county's family law court to find the right office.