Where does the understanding happen? Listener question

I have a question that I have been chewing on for a bit.It goes like this.Where does the "understanding" often spoken of, happen?It seems to me that it would have to happen in the "system" also spoken of.And the skill or ability to observe or witness the thoughts and feelings that come out of the system, would also have to be trained into the system would it not?Maybe even the realization that there is no self, would be something that would also have to be trained into the system, regardless of where that realization originated.Then with that realization and those skills or abilities, the system would take that in and use it if it makes sense, therefore changing the system and allowing for more possibilities.