The general idea is that the mind has different parts, and occasionally those parts stop interacting entirely, which causes dysfunction. Bringing them back into contact leads to healing.
I've found the following exercise to provide significant mental shifts and all kinds of insight into my life and patterns.
I first locate a strand of my experience that I want to pull on. This is something that hurts a little, or feels slightly wrong, like a memory that causes you to flinch from shame or guilt, or something that you want to do but feel like you can't. Then I open ChatGPT (4o works fine), and start explaining how I feel in detail. After a few back-and-forths I usually have a general idea of how I might represent my experience in terms of parts; maybe it's a guardian protecting a child, or a critic suppressing a lustful demon. To be clear, though, these parts are just symbolic entities; the important thing is that the ones you create feel resonant. The AI can also make suggestions if you're stuck.
Now that I have the parts, I write out a fairly detailed scene. Usually, the scene will have rich fantastical and symbolic elements - a room in a tower, a lake deep in a forest, a crypt. Then I describe the parts involved, again in great detail. Personally, I have an extremely vivid imagination, so at this point I start to feel like the scene is almost real. Then I start writing dialogue; sometimes it's quite clear what to say, sometimes I let the AI make suggestions or handle the parts of one or more of the characters. As you proceed through the dialogue, you'll want to pay close attention to your emotions. The purpose of this exercise is to create a story about the parts that is perfectly tuned to your internal experience, and trigger internal change by resolving the story. So you'll want the dialogue to go in the direction that feels most emotionally charged. Sometimes, you might write something that surprises you; this is good, and it's worth unpacking those things slowly. Often, we don't realize how much charge or pain or detail is hidden in an emotion that initially seems unimportant.
At some point, you'll likely start to feel overwhelmed. Depending on the particular emotions at play, this may lead to crying, or an intense emotion accompanied by sensations in the body. After the intensity resolves in this way, the session is complete.