Try to have a 30 day stay in the Phils. That is the maximum allowed there without a visa.
It is your partner who needs to get a CENOMAR from NSO, not you. She will also need a Cedula.
The civil ceremony would normally take place in a local (partner's ?) town/city hall . Handily, this is also normally the location of the Registrar's office.
Your partner just needs to go along there ASAP to find out what their requirements from each party will be. They will often give out a printed list.
Some Filipino documents are available online now.
Google is your friend.![]()