The problem with this is, that it is only an intellectual concept when you tell it. How do you noticing without judgement? I could also tell you, that mindfulness is when you feel green. You understand the concept of green, but how do you feel green? Telling or knowing that you need to accept without judgement is practically worthless.

Your unconscious permanently judge its environment and it doesn't care what your conscious intellectual thinks. It still functions in the normal reaction patterns. If something is nice, it wants it and want to keep it. If something is bad, it wants to change it. This reaction pattern needs to change.

The key to know is, how do you train your unconscious to break the lifelong trained reaction patterns? One of the best ways is the vipassana meditation that is attributed to Buddha.

Sit still and make a body scan. The reason for this is, that your unconscious always is conscious about how your body feels. And when you make your body scan, your conscious and your unconscious are on the same place at the same time. Now sit still for an hour without moving. This is uncomfortable and your unconscious want you to move, but your conscious stops your movement. This is the situation you use to train your unconscious to understand to not judge a situation is better than wanting something. If it wanting you to move, it gets more uncomfortable than accepting the situation.

The best way to learn this, is to do a 10 day vipassna retreat, where you meditate 10 hours a day. A 10 day retreat let you reach a practice that is impossible for most to reach in years. They have three times a day a sitting of strong determination in a group where everyone tries not to move for an hour while doing a body scan.

The hour starts with singing and telling you what to do. Than there is silence. In the hour, you only scan your body. Start with the top of your head and try to feel something. If you feel something, move further till you scanned trough your whole body. When you reach your feet, do the same in reverse. When you are in some part of your body and you get a strong sensation in an other part of your body, ignore it. Do your scan without jumping from strong sensation to strong sensations. Don't move, no matter what. Your Eyes should be closed the whole time. This hour is uncomfortable and your unconscious wants you to move. This makes it more uncomfortable. The hour ends with singing for a few minutes (you don't sing).

After some time, you are so sensible to your body feelings, that your conscious and your unconscious feels at the same time that wanting to change the situation makes the hour worse. When you want the hour to end and wish that the singing starts, you instantly feel how your situation got worse. When you stop wishing the hour to end, it gets better. You also feel, that a uncomfortable situation is not uncomfortable all the time. Everything changes all the time. This is when you unconscious learn to accept without judgement.

But i can you tell this, and it will do nothing to you. I can not walk the way for you. Everyone needs to walk the way for himself. It stays an intellectual concept for you and your unconscious still will react within its trained reactions patterns, till you start to teach it.