How to become nothing

You can't go nowhere, but if you want to calm your mind, I recommend zazen.
Please look for a place where zazen sessions are held at a Zen temple near you.
I think temples that have zazen ceremonies have information on the internet or on the bulletin board in front of the temple gate.

Also, if you're organizing your thoughts, it might be easier to organize them by thinking while writing on paper rather than thinking in your head.

I believe that becoming nothing begins with objectively viewing the self reflected in the mirror, feeling as if we are an ethereal being without being caught by anything.
From the standpoint of a Zen monk, I should recommend starting with zazen, but if you can take a quick walk, look down at the scenery from the top of a hill, and think that things that are taken up on a daily basis can eventually be solved, then they can come to nothing.
Why don't you start with small actions?

　The brain is constantly in motion, so we cannot lose our mind.
For example, if you think “let's lose our heart,” our heart is filled with the feeling of “let's lose our heart.”

We, the monks of the Soto sect, do not lose our heart during zazen, but rather “let go.” I don't get involved with what comes to mind; I just accept it as it is.

Rather than losing one's mind, I think the question is about how to reset one's feelings and how one can change one's mind.
I recommend tidying up and cleaning the room. Since you move your body, it's an exercise, and when your room is tidy and clean, it makes you feel new.

Try just tidying up and cleaning without being too aware of “nothing” or chewing things up. Doing so will clear your mind.

It's just an image story, but bad emotions produce poisonous juice in the brain.
There are things you don't like, and if you keep thinking about them forever, your bad feelings will continue.
This means your brain is overflowing with poisonous juice, and your mind is soaked in a bath of poisonous juice.
So, first you need to get out of the bath of poisonous juice. As much as possible, it is necessary to stay out of the toxic bath as often or for as long as possible.
In other words, don't think about bad things, make time to think about other things, and make time not immersed in bad feelings.
What should I do?
As a test, while saying “aiueo” with your mouth,
At the same time, try reading “one two three four five” in your mind.
Your mind wants to put in distractions such as “why do I have to do this” even if there is a gap of how many seconds between the commas “1” and “2,” but please concentrate on “one two three four five” as much as possible. It may be easier for the body to concentrate when it stops moving.
If you do that, your mind will be busy, and you won't have time to soak in a toxic bath.
If you grasp that feeling, it may become a “weapon” for emotional reset.
As a reminder, try making a smile while thinking “I'm out of the poison bath” after repeating “aiueo” and “one two three four five” several times.