The first stages of this are simple, and anyone can do it. The latter stages are quite technical.
Sit or recline comfortably.
Focus the mind on one point, like a mantra or the breath. Do this for 10 minutes.
Then, open your awareness to all sensations without focusing on anything in particular. Sounds, smells, emotions, thoughts. Do this for 10 minutes.
Don't think about what's causing them, what you can do to fix them, or what kind of person they makes you.
Accept without judgement.
Feel the relief.
Do this for 10 minutes, then repeat the cycle.
You may sometimes get some very pleasant euphoric states.
After a few months, you will likely process all the surface / recent emotions and gain a deeper sense of well being.
Once you shut up the mental chatter, notice that most of what you feel as emotions happens in the body, not in thoughts.
Zoom in. Investigate where in the body you are feeling the emotions. Focus awareness there.
You may get a euphoric, full-body sense of release.
Attachments drop. You feel lighter and have more clarity.
At this point you've investigated thoroughly where in the body the sensations happen and what their qualities are.
Now zoom in to micro level and notice how each sensation forms a pulse or wave pattern (sub-second).
Something arises, then subsides, arises, subsides.
Now notice the space between the pulses / waves. The emptiness, the Void.
Notice that each wave of the sensation arises from this Void, and then returns to it.
Observe the qualities of the Void. The sense of freedom in it.
Notice how the one observing all this is separate from the wave.
How could you observe the wave, unless you aren't the wave?
And when you notice this, there comes a certain sense of detachment and relief.
"Oh, I am just watching this wave happening".
Take the observer and plunge it into the sensation. Come into complete resonance with the wave, become one with it on a micro level.
At this point, the sensation ceizes. The wave doesn't experience itself as the wave.
Now, try to find the observer.
It's not there!
It gets increasingly intense as you get closer to it, then suddenly you're submerged in nothingness and time stands still for an immeasurable period.
Then, just as suddenly, you get spit out on the other side and wonder what just happened.
You realize it's not a duality.
Not only is there no division between the observer and the sensations,
but the observer does't exist. And the sensations are just waves arising from the Void.
There is no "self".
But it often takes seeing it with enough of your being for it to "click".
This is why shutting up the mental chatter and releasing the emotions first helps immensely.
I'd already had close to no mental chatter for months at that point from doing a ton of meditation, so it hit like a supernova.
Cue the self annihilation meme.
That was an interesting discovery, but it's just a side note.
It's a deeply unpleasant experience, but it is cathartic in a major way.
Make no mistake, it a destructive event of massive proportions.
The insight might come as a distinct event, but the work doesn't stop after. It's a long process.
The real work of meditation begins after awakening, as they say.
The mind begins to restructure itself in major ways. The personality often dissolves and then recoheres in a new form. The world view shifts. Behaviors change.
And peace of mind does come eventually, but what they don't tell you is what lies between the starting point and that peace!
There is no perfect peace of mind, perfect clarify, perfect self control, perfect cessation of craving or anger or suffering. It's a myth.
You just get better at it.
It's the cosmic joke.
You are still you, in the deepest sense.
You are and have always been the cosmic evolutionary process becoming aware of itself.
There is a part of you that already knows and has always known all this.
The other parts of you are just waking up to it and joining the party. Which is why the term "awakening" is fitting.
The cosmic joke continues!
There are lots of other ways it can be done.
But I also know people who've had various awakenings through:
- tantric practices
- reading a profound book
- help of a guru
It also seems that dissolving the framework is a good idea after the work is done, so it doesn't turn into dogma.
My own bias was pointed out to me in this post by @OortCloudAtlas.
I mainly talked about awakening to the realization that there is no self. But I failed to mention another important part.
It produced a long period of "I am crazy", and I don't think I integrated it properly back then. So I dismissed it as less important because of those circumstances.
Having a framework and a solid meditation practice are really useful for integrating spiritual insights. Insights had outside of a framework can create a long period of "I am crazy", can be difficult to integrate, or can get dismissed altogether.
Seeing as that's what your mind is doing anyway, constantly creating & projecting a model of reality, it's a good thing.