I cut the stems about 8 inches, even a little longer, just below a nodule. Take off most of the leaves, even any flowers, leaving just a few leaves at the top. I root them in clear plastic cups, or cheap glass vase. Lots of light, no direct sun. Change water every few days. Eventually you will see roots forming by the nodule. When there's a decent root system, you can plant; keep them watered regularly until they are established. Don't forget to keep the seeds. I let the seeds of some of my plants just blow wherever. Then if it's not in the place I want, they're easy to transplant while small.
Hope this helps.
