Adding steam to your home is a great idea which you will thank yourself for repeatedly.
You can add steam to your existing shower environment or create a new one. What you must have is a waterproof environment that is fully enclosed...your shower door wall must go to the ceiling. Check here to learn about steam room design http://www.steamsaunabath.com//catalog/all_about_steam_rooms.php
With the proper environment, simply install the generator and control along with any other features you would like to incorporate into your steam shower and enjoy! Feel free to use your own contractor or you can find one through the installation network found here http://www.steamsaunabath.com//catalog/installation.php#network