A sauna is a dry, hot room. It causes you to sweat profusely, thereby removing toxins from your body through sweat. A steam room, on the other hand, involves you sitting in a room filled with steam. Both are equally good for relaxation and detoxification, but I personally prefer steam rooms to saunas.
Choosing hot tubes for one person is quite difficult. There are a lot of options on the market right now, but believe me, it's better to spend time and choose the perfect option for yourself than to regret it later. I've never tasted anything better in my life.