It’s a bit more involved. You need to vacuum seal your food so you have a consistent temperature across entirety of the surface. You don’t really boil the water either, you have to keep it as an exact temperature and keep it circulating. That way you can cook food in seasonings and marinades to a perfect temperature then pan sear afterward for color with out losing any juices.

If you just throw food in a bag and boil it, you’ll probably be disappointed with the comparison to actual sous vide cooking.