Okay, I will try to verbalise how I understand how schema therapy works.
Because having knee problems at the moment it is funny how I make analogy between physiotherapeutic massage that releases tense muscles that accumulated over time and schema therapy sessions that release tense emotions that accumulated over time. In both cases it is remarkable how much pain such accumulated tension can cause. The pain is so strong that it is hard to believe that it could come from something as trivial as tension, and it is hard to believe that releasing the tension could solve anything major. But it is so. Something that felt clearly "broken" turns out to be merely "misaligned".
Schema therapy principle sounds too trivial, but its secret lays in all that is built on top of the trivial basic things, just like the whole body weight depends on the ankles and knees. One muscle having wrong flexing pattern can eventually lead to spine injury. One emotional wound from childhood can bring someone to the verge of suicide. Fixing something that appears trivial causes a chain reaction that slowly but steadily improves the overall condition.
One aspect of schema therapy is giving the patient a model of their problems that they can work with. The model consists of schemas. That part I skip here as it can be found on the Internet, and it actually overlaps with what I called "personas" in my other post.
What is more interesting is the practical part and this is what I want to describe, as I believe that with some prerequisite work anyone has the capacity to apply this method on their own. With the therapist it is just much faster. But even if healing of one wound was supposed to take 1 year instead of 1 hour it is still worth it. In the end it may cost a life.
From my perspective it works like this: whenever you have a strong unpleasant emotional reaction that puts you into trouble, apply those steps (in therapy session this process lasts an hour, on one's own I can easily imagine being stuck on each step for a few months.. but in the end the longer one practices, the more one is able to do it on their own. So it's not about the number of successful runs of that process but about the overall duration of trying).
  1. Think about the recent situation that made you feel bad. Even better if you still feel so (though may require more effort).

  2. Focus on your body. Try to find out what sensations are in your body, how you feel on a purely physical level. Which part of the body is tense, maybe you feel heat, maybe you sweat, maybe your heart beats fast, how is your breathing. I think that most people would get stuck on this step, as this is about body awareness that is a skill being less and less exercised in current times of living "online". But improving this skill is very useful anyhow. And it is a skill, and can be exercised as any other skill. Vipassana helped me a lot in this, also dancing, physical exercise, and human touch (i.e. hugging my friends for hello and goodbye, whether they like it or not :D).

  3. Hold on to that body feeling and forget about the situation. Just the body. Close your eyes, and ask yourself when did you feel like this in your body as a child? For me usually the first answer is "how the heck shall I know?!", and then I get a random memory which seems totally unrelated at the first sight. If you don't get a memory you can just give yourself a break. You're not in a session with a therapist whom you paid a lot of money, so there is no rush Try again on another day, maybe with this feeling maybe with another. They tend to be repetitive anyway.

  4. From the point of view of the little child, speaking in first person, describe what is happening. For example "I am sitting in my room, my mother is shouting at me". Next describe how you feel and list the feelings (you can use an online list of feelings if this step is difficult). For example "scared", "dissapointed", etc.

    It is important to stay focused and not get sucked into the memory, to still have the possibility to look at the situation both from the point of view of little emotional child and the adult current you. It's funny how we people who cannot take care about ourselves can see what other people need and give them the right advice. That's what needs to be done in that moment - to know how the child feels, while maintaining the ability to get in and out of this little child's emotional state. It's like pressing the "pause" button in the memory to analyse it.

  5. Next you ask yourself: what do I need (being the child)? What do I wish for in this moment, emotionally? Let the child answer. E.g. "I need to know I am okay", or "I need my mum to leave me alone". Then shift back to the adult and think of how you could the situation could be helped so that the child's need is met. Usually it involves inviting someone else into the scene - a good current friend, a past friend, the adult you, and letting them interact with the people in the scene, stand up for the child, help the child bring their message forward, express those emotions you just listed - and get them addressed. Don't force anything, and don't reject any idea - just follow what the child feels comfortable with. The child is the king and the director :p In therapy often therapist enters the scene as the new person. Often as much as an objective summary of how the situation is affecting the child is enough. Imaginary dialogs happen.

    I think in those moments the emotional memory can actually get altered. And while it seems like not such a big deal, it can start a chain reaction days and weeks after. The goal is to achieve a state when the child feels relieved and back at ease. I'm not sure why the therapist always insist that I say what I want to do next as the child, e.g. go play. But I have to admit that such idea comes up quite naturally once the child is calmed down.

  6. But the work is not done yet. Once the imaginary part is done it's important to make a link from reality to that emotional resolution. So what we do then with the therapist we sit back and analyse which moment exactly caused the child to calm down and feel relief. What exactly happened there. Then we try to take something away from that thing, like a certain sentence to repeat to myself when I'm triggered next time, or maybe something that brings up a memory of a certain person who stood up for the child in that fabricated memory. I think for that part I am not yet that good on my own, and I appreciate how my therapist is able to come up with ideas that later actually work.
I have now three memories addressed in such process and I have to say that I have noticed myself feeling calm in situations in which I would normally freak out. It's an amazing feeling.