When you first begin this practice, repeat this process several times. You will reach the conclusion that everything in your body, and your body as a whole, is energy and nothing else. Then, whatever you are sitting on is matter and thus energy. The air is energy. The warmth of the air is energy.
Light is energy.
People and animals are energy. All are characterized by non duality and nondiscrimination. Whenever your mind wavers and cannot keep expanding your vision of energy, then retreat to the point where your vision of energy is clear. Since energy is a good analogy for Original Nature, this practice can be very effective. It is simple yet in harmony with Original Nature.