Water is a common propagation method for Aroids, as their roots can adapt easily to a multitude of environments. When using water to propagate, you should change the water out regularly, and add a drop of fertilizer at each change.
After selecting and cutting the plant you wish to propagate, allow 12-24 hours for the fresh cuts to callous over. This drying out process will help prevent rot from forming, and help promote a successful propagation. I would advise starting with at least one root, or a newly emerged root bud. After you have allowed the cutting to callous over, simply place your cutting in a clean vessel of water.