Citizenship by descent

ᜃᜓᜓᜌ_ᜇᜒᜌᜋᜒ

Hello everyone,
I am an Australian citizen, my partner is a Filipina living in the Philippines. She recently gave birth to our firstborn son in Manila. I was present at the birth, I am listed as the father on our baby's birth certificate but my partner and I are not yet married. What are the steps required, documentation needed to process my son's citizenship by descent.
Was hoping if anyone who has been through the process for their advice, as well as any migration agent who may frequent this forum.

Thanks po in advance.