The three Buddha secrets allow us to experience the Buddha nature of the universe and ourselves as one. The following Alan Watts video may be helpful in understanding the Buddhist Secrets:
Mudras — The Secret of the Body
The hand gestures known as mudras identify the practitioner with the universe and express the hidden activity of the body. The human body is reflective, as a symbol of the larger universe. It is one way to begin resonating with the field of energies held intact by the Buddha’s.
Speech – The Secret of Speech
The activity of speech known as mantra expresses another secret activity. A place where one can “sound” the resonate field of energy, thus coming into alignment with the Buddha’s through the reciting of sacred formulas called Dharanis.
Internal Visualization – The Secret of Mind
The secret activity of the mind is done through the internalization visually of the Buddha’s and other deities, seed symbols, and forms. The activity represents the presence throughout all phenomenon of the mind of the universe or the mind of Mahavairocana / Dainichi Nyorai.
Secret of the Body
Let every action you undertake in life be the action of Mahavairocana / Dainichi Nyorai.
Secret of Speech
Let every word uttered, be of the same uplifting purity that is the sound essence of Mahavairocana / Dainichi Nyorai.
Secret of Mind
Let every thought, and imagining be as all the wondrous blessings we see in the universe, the perfection that is Mahavairocana / Dainichi Nyorai.