In 2021 EVERYONE (Coaches and Managers) who is involved with children i.e. people under 18, will need to get a Working with children check.
As a volunteer-this should be free.
go to this site:
and apply for a WWC by filling out the online application.
Take the number supplied with your selected photo ID to your nearest Service NSW office.
Then register for your volunteer position and enter the details of your WWC at registration.