For all Morning Glory seeds - soak in warm water at least 24 hours. For larger seeds, nick or sand paper scarify them. For ipomea moonflower they must be nicked.
I usually soak in hydrogen peroxide solution and use that solution to water all my seedlings and ,oistening the media when I plant the seeds.
I typically do not grow Morning glories indoors, but start them outdoors. Had best luck that way. When I do start them indoors, I start about a month before last frost and use bottom heat and lights.