Catholic Guy Says, 'This is not the way to do it.'

Sorry for the typo at the 38 sec. mark : (they're not their).
The Ontological Argument is basically 'If God, defined as the maximally greatest conceivable being, can possibly exist then he therefore must exist'. So, it is argued that if God could exist in any logically possible worlds, then he does exist in at least one possible world. But if he is maximally great, he should exist in every logically possible world. Therefore, he exists in this world.

The presuppositional approach would be that what is logically possible, and argumentation itself necessarily assumes the existence of the Christian God, for his nature is metaphysically necessary for logic itself and our capacity to accurately engage in it.
see here for our presupp series • Street Presupp