Thanks for the links. I'm starting to get the feeling I may not be meant to have dragon fruit. First the seller sent me the wrong plant entirely, and then I received my cuttings, but they had no roots, even though the seller promised rooted cuttings. One looks like it might be okay, but then other seems like it probably won't make it.
I'm going to try again ordering from another seller. I also ordered some rooting hormone to try to save my cutting that is stubbornly refusing to root, but I'm not optimistic. Hopefully this other seller sends the correct plants and they do better. At least this time I'll be prepared and have rooting hormone on hand if these come without roots, too. And maybe it's better. This other seller had more varieties, so I ordered sugar dragon and purple haze cuttings, so if these do well I'll get to try a few different types.