The (British ?) partner to whom the Affidavit/Affirmation refers, needs to present himself and the completed ( but not signed) form to the officer at the embassy in Manila. An appointment needs to be made first. All of this information is available online on the British Embassy website.... and the forms to download... and the facility to book the appointment.
As a disciple of Richard Dawkins / the late Christopher Hitchens I can't offer advice on the religious side of nuptials --- but welcome to the Forum. Great bunch of chaps and chapesses here!