First we concentrate the mind. Once the mind is focused/sharp, you can begin to feel subtle sensations and feelings in the body you don’t normally feel. These sensations can be pleasant or unpleasant, but they key is to recognize that they are impermanent; they will eventually pass. The habit pattern of the mind is to react to pleasant sensations with craving, and unpleasant sensations with aversion. The key is to understand that sensations cause reactions. Learn to observe these sensations, and not react, because these sensations are impermanent and will eventually pass. This process of observation without reaction is referred to as developing equanimity.