Apply seeds to finely sifted soil and grit/coarse sand in a sealed takeaway container. Spray wet until damp but not soaked. Keep modestly lit (no direct sunlight) and warm. Seeds sprout-- Easy as can be-- cool thing is they can stay in that original sealed container for a year or more without you having to do anything-- look up Takeaway Tek online and you'll see-- super easy and it's the method I use for my Trichocereus cactus.

Yes, I know, have two multihead caespitosa specimen in my collection, which already had some flowers this year. But they are much smaller, so it is going to take at least two additional years to harvesting.