It sounds like what you're describing is the practice-less practices of Advaita Vedanta, Dzogchen and in Zen, "Shikantaza."

You'll find countless excellent descriptions of how (or not how!) to "do" this. The best I've seen recently is from Angelo Dilullo's book, "Awake." He refers to it as natural meditation. Forgive the length but I think it's worth it:

Natural meditation is best defined by what it is not: (he even recommends reading this through each time you meditate until it starts to feel natural)

It’s not a practice.

It’s not a technique.

It’s not something you can do wrong.

It’s not a means to an end.

It’s not focusing your attention in a certain way.

It’s not about trying to witness something.

It’s not about trying to label something.

It’s not trying to create a state.

It’s not trying to relax.

It’s not trying to heal the body, mind, or heart.

It’s not something you have to get better at.

It’s not something meant to cause enlightenment.

It’s not trying to make anything happen.

It’s not trying to stop something from happening.

It’s not trying to find out who you are.

It’s not trying to forget who you are.

It’s not trying to get rid of anything.

It’s not trying to gain anything.

Here’s how you do it:

Put away all distractions, including electronics, screens, etc.

Sit or lie in a comfortable position.

Sitting is better if you tend to easily fall asleep when lying down.

Let go of all agendas.

Don’t try to do anything or make anything happen. Don’t try to manage your experience.

Don’t judge. This means there is no such thing as “too many thoughts,” or “an annoying sound.”

Let everything be as it is.

*****

In a Dzogchen workshop i took many years ago from Alan Wallace, he put it even more simply:

"Do nothing."

The only additional thing he said was to set an intention - when thoughts begin to link up (and he held up two fingers with fingertips touch as he said this) with the most effortless effort, release (spreading the two fingers apart) and again, continue doing nothing.

.