Hello!
You wrote that You have complete understanding of levels 2, 3 and almost level 4. But what about lvl completion? What about verifying lvl completion on e-meter? And what about RI(lvl1)? I think complete understanding of each lvl might appear only when lvl is finished. Also doing lvl5 without other levels finished might be dangerous. I had that experience.
You asked to give explanation in onw words. I'll try, but please, don't do that before all others lvls finished.
The idea of lvl5 is to use raw postulates and game situations. Raw postulate is pure goal without any specific object\effect. For example, postulate "I want to eat hot dog" is not raw. "I want to eat something" looks better. Lets change some words: "I want to eat something" = "I want to feel taste and fullnes" = "I want to know feeling of taste and fullnes". So it's not raw too because there are concrete objects (concrete taste and fillnes). But the postulate "I want to know feeling of taste and fullnes" = "I want to know" is raw enough. "I want to know" includes all situations with eating hot dogs and other food. So we can't work with raw postulate instead of working with particular.
So in TROM and Scientology PC tries to do consciously what Reactive Mind does automatically. PC does it to overcome the automaticity of reactive mind. At lvl5 PC creates two postulate: one for himself and second for the other. It's very simple. Create your desire to know something in front of you. Create someone else desire to prevent you from knowing in other place. Hold both some time. At that moment a lot of charge goes off, it dissapears and you need a lot of RI. Or you need to go to a hospital if previous lvls undone. You do what your mind does automatically. You create two postulates in opposition, and your mind does the same all time of your life but in silent mode.