Parent volunteer

Hi mommies... I would like to ask some questions . Coz Its my new experience to apply my first son to p1 next year. How to apply as PV in our son school that we want to enroll? Is it true must apply 1 year before n minimum have 40 hours. ? But when I called n email one of primary that i choose. They told me I can apply as PV after my kid enroll to their school. Please give me advice. Thankyou