I've always found it pretty easy - I've raised a few batches all the way to moths. I've used both an old school hovabator incubator with water in the bottom (during colder months) or just any container with some moist paper towels in the bottom, and then I put the petri dish they come in into that container, so the ambient humidity is high but the eggs themselves are kept dry.
Then I use some little pieces of fiberglass windowscreen to give them food - the food goes onto the windowscreen, the worms crawl up through the holes onto the food, and you can discard the poop, eggs, dead worms below. Once they're too big for the windowscreen IME they're robust enough to not randomly die.
Stray thoughts:
- fresh leaves work better than chow if you have access to them. Now is the time of year to get them, at least on the West Coast where I live.
- Don't feed leaves if you plan to use chow at any point, they don't transition back well.
- I always buy from Amazon and I've never had a problem hatching them. I think I've been getting them from coastal silkworms.