|How do you grasp Nothingness?|
The first and obvious level is to not disengage from thoughts and concepts. During meditation, you will notice that thoughts come up. Your only task is then to stop following them, let them go and refocus on your chosen object of meditation. This could be your breath for example. Thoughts are concepts, that are playing themselves out in time. Thoughts are always about something that has happened in the past or something that you plan to do.
The second and less obvious level to disengage from is the concept of the meditation object itself. This is a little bit tricky and usually takes some practice to get clear about what is meant by this. For example, you might choose the breath as your object of meditation. With your awareness, you follow the breath going in and out of your nostrils.
Here it can be the case that you are not really present, but you are focused on the concept of the breath. This could mean that you are thinking of the breath as being one thing that is made up of breathing in and then breathing out. And then you are also aware that you are going to follow this breath for the rest of your meditation session. Your awareness is not in the present moment, it is on a concept or the story of you meditating.
You want to consider the following aspect in order to arrive at the non-dual level with your meditation. When you are doing the practice right, you have to let go completely of all conceptualization, including the concept that you are meditating and the breath as the concept described above. The goal is to let your breath take you into the unmanifest present moment.
And you do that by continually refocusing on what is actually going on. Not in thought, not in concept, but actually in this moment. And every conceptualization happens really fast and unconsciously. You have to be even more present. That means looking that everything how it arises in the blink of an eye, every millisecond. Catch the breath, before it becomes the breath. And then you want to connect to that level continuously.
When you notice a concept is arising, you briefly recognize it and imagine that it dissolves into white light. Don't spend much time on this. You can do this only for a second or two and it is enough. It is only important that you quickly reconnect awareness of the present moment. And here you will quickly realize that it is actually utterly empty. Without concept, you can only be aware of awareness itself. Before concept, there is nothing there.
Don't be frustrated if you are constantly pulled back into your concept of the meditation object. To some degree, it will always be there, but you also want to learn how to go beyond that in order to see what lies there. To see the fabric of reality so to speak.
In the beginning, this is really hard. And practice will mean, that you refocus hundreds of times in every meditation session. Sometimes every second. As mentioned, concepts creep in really fast and letting go of them is not the default mode. But with practice, it can be done. And then the oneness in every moment is revealed. As well as its inherently empty, timeless and infinite nature. Neti Neti.