找块稳固牢靠的地方坐下来或者躺下来。 放松身心。 用横膈膜缓慢吸气。 每次吐气时，只吐一点点。 反复训练呼吸。

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Find comfortable ground to lay down on or sit upright on your knees. Practice holding your breath for long periods of time out of water first so you can practice proper breathing techniques. While lying down or sitting, focus on clearing your mind of all extra thoughts and worries. Don't move your body around; sit as still as possible. This lowers your blood pulse. A lowered pulse means your body is using less oxygen.  Your body needs oxygen to move and function. The less you move, the less oxyg