Being is the Who. The things you cannot physically see or touch. Being includes awareness, thinking, feeling, and skills.
Doing is the What. Actions you take and tasks you perform. Doing includes motion, effort, action, and physical functions.
While the Being focuses on emotional or intellectual energy, the Doing focuses on physical or mechanical energy. 
Now, let’s over-simplify: if you focus only on the being, who you are, and refrain from doing, your value and existence are limited. The Doing is how you eat, breathe, sleep, and support yourself financially. If you focus on the doing to the exclusion of the being, your value and efforts are limited. The Being is how you process information, consider choices, and make decisions.
When you maximize both the Being and the Doing, and even better coordinate the two, you maximize your potential.
There are times when a focus on only the Being or only the Doing is important or even necessary. Of course, the other continues to operate even if minimally.
How can a coach prepare to work with both the Being and the Doing? To state the obvious, start with coach training. Earning membership in the International Coach Federation, ICF, really is a minimum standard for calling yourself a coach. Coach-specific training teaches the ethics and competencies. Both are foundational to Doing and to Being. Then, keep going. Move on to earning a credential with the ICF. As an illustration, at the first level of credentialing, the ACC, a focus primarily on the Doing is considered acceptable. At the PCC and MCC levels a focus primarily on the Doing is expected. It is easy to then extrapolate that the significance of Being in a coaching relationship is very high, and that developing the skill for that focus takes time and experience.
