When one of mine flowered last summer, the stalk grew to be about 18 inches tall.
Once the tiny star like flowers started opening I pollinated with a very small paintbrush, every day, I think it was for a week or two.
I was pleasantly surprised when I got some seeds, since I'd never had a Ceph flower before. The seeds were small and fuzzy, looking similar to tiny feathers, tan colored.
I ended up getting about 20 seedlings!! They are tiny now, maybe 1/8th inch or so.