Recognise the Spaciousness in which the world appears. Sights and sounds, thoughts and feelings, all appear in something. They cannot appear or be known without a field in which they appear. For example, a thought pops into the mind, "I must remember to call Jasper." The thought is perceived or known. It's difficult to say what the thought appears in, but it's a kind of empty space. We call it consciousness or the mind.
Take another example: we hear the sound of a car driving past. There is an awareness or knowing of the sound. There is a field like silence in which the sound comes and goes. It's not altogether different to how thoughts come and go in a space of awareness. It is ultimately the same space of awareness that perceives or knows the sound and the thought. The knowing of these is like the centre of perception. It is the same space in which all perceptions are experienced. Sights, smells, taste, touch, feelings, are all experienced in the same place of knowing.
So our practice is to recognise that space in which all things are perceived, known or experienced. We are that Infinite Spaciousness. How wide or deep is it? No width, no depth. It has no size because it is limitless and formless. It is that which perceives apparent limits and forms, yet is itself limitless and formless. Any limits of things are imaginary or conceptual. These imaginary or conceptual limits are perceived in this Knowing Spaciousness. Recognise this. We perceive the thoughts and ideas of things being limited. We perceive the sense of the world being made of separate forms. But this is just an idea or assumption of limitation and division in the world. The world we experience is only ever experienced in one place. The sense of distance and time is experienced in this Knowing Spaciousness right Here and Now.
Knowing Spaciousness can't really be known, as it is Knowing itself. Just as the eye cannot see the eye. But we can know it is here because we know. In other words, I know therefore I am.
The practice is to recognise that even the person or personality is known. We are not the person, the thinker or the body doing actions. Recognise that these are perceived and we are That which is naturally perceiving, or Aware. Thoughts float by in the Spaciousness of Consciousness like clouds drifting through the endless sky. Spaciousness is unaffected by whatever appears because it has no form or substance. Yet it is the Full Emptiness in which all things appear.
Who is it that is doing this practice or seeking to be aware of this Knowing Spaciousness. Truly there is no-one. There isn't really a limited person trying to do this. It is an activity in the mind. It's an activity of the sense of being someone seeking to find who knows this. It may seem a little odd, but basically it is Self Enquiry. It is the sense of self seeking its source. Recognise that this is perceived. This seeking is perceived. It is not who we are. We are the the knowing of this. We are the Knowing Spaciousness.