The word soma means body in Greek. For our purpose, it represents anything physical, physiological or pertaining to the body. In that dimension, you have to learn to observe your body: how it senses, its degree of comfort or discomfort, its level of energy or fatigue, its strength or weakness, flexibility or rigidity, etc. There is no need for elaborate analysis: just put words to what you experience physically. In this list of Words for Soma you will find suggestions for words that describe physical experiences.
As you will see, some words describe some negative bodily or physical experiences or states, while others describe positive ones. It can be useful to divide all these physical states into two broad categories: one for physical experiences that would be more conducive to happiness, and the other for physical experiences that would be predominantly non-conducive to happiness. Simply put, a conducive state would promote feeling rested, reasonably fit and as comfortable as you can, within the limits of any physical limitations or illnesses you may have. On the other hand, fatigue, lack of energy, lack of comfort and feeling considerable pain would be non-conducive to happiness.
After this is done, proceed to the next dimension: Emotion.