Dragon Fruit Germination:
1) Soak seeds in water for 36 hours.
2) Use a heated propagator mat to keep the soil at 80-85 degrees F.
3) Use a well mixed & well draining seed starting mix, and plant the seeds appx. 1/4-3/8" inches deep.
4) Use a grow light, or keep them in a sunny window.
5) Keep soil moist, but not wet at all times.
6) Dragon Fruit seeds are small & fragile, so use a spray bottle to mist them so the seeds don't get jostled & buried to deep as that will cause them to rot. 
7) Germination is erratic and can occur anywhere from 1-8 weeks, so don't toss out any that don't sprout quickly.