Cal. Elec. Code § 10304
The Governor shall issue a commission to the commissioners, and the issuance of the commission shall be conclusive evidence of the regularity of all the proceedings to and including the appointment of the commissioners. Within 10 days after their appointment, the commissioners shall take the constitutional oath of office before some officer authorized to administer oaths. The oath shall be indorsed upon the commission, and a copy filed in the office of the Secretary of State. The commission shall organize by the election of a president and secretary from their own members. The commission shall keep minutes of all its proceedings, which minutes shall be signed at the close of each meeting by the president and secretary.
Ca. Elec. Code § 10304