When you first begin this practice, repeat the process several times. You will reach the conclusion that everything in your body, as well as your body as a whole, is energy and nothing else. Then realize that 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 is characterized by nonduality and nondiscrimination. Whenever your mind wavers and you cannot keep expanding your vision of energy while meditating thusly, retreat to a point where your vision of energy is clear. Since energy is a good analogy for basic nature, this practice can be very effective. It is simple, yet in harmony with the profound level of basic nature.