I'm still somewhat of a passiflora novice and have only been growing them for a few years. All my passies are container grown. This is the first year that I'm growing plants from my own seeds, though I've propagated many of my plants from cuttings.

Wait for the fruit to drop from the vine, don't pick it. You want it to be very ripe to make sure the seeds have matured. Not all fruit will contain seeds. I've had plenty of fruit that are nothing more than air filled sacks. If you have seeds you'll want to plant them ASAP for the best germination results. Remove the pulp from the seeds and put them in a moist potting medium. Some people soak them in oj first but I think the fresh ones can be sowed directly. I've only had good germination results using a seed mat for bottom heat and some varieties sprout much faster than others. Do a search in this forum about starting passiflora seeds and you'll get some good info. Good luck.
Karyn