Test Heat Before Sitting Over Steam.
Let it cool down until it feels relaxing like a warm bath.
It should be 100% comfortable and soothing.
(Note: If at any point you have the instinct to get up because it's too hot then you should let the steam cool for a minute before resuming your session. If you are using an electric burner (sold separately) for an advanced session, turn off the burner and wait for the steam to cool down.)
If you are having trouble controlling the heat level, please follow the directions for the Mild Steam Setup.