Mind itself, buddha nature, is empty, clear, unceasing awareness. When you experience that mind is empty, devoid of intrinsic being, you are taking refuge in buddha.
Dharma is clarity
To take refuge in the Dharma is to experience the clarity of awareness itself, a clarity that doesn't come from anywhere, doesn't go anywhere, and is not located anywhere.
Sangha is unceasing experience
When you experience no separation from the constant arising and subsiding of experience, you are taking refuge in the Sangha.