What's the Key Component of the Numbering System?

Every card had an idea number. He had a hold process for putting new notes in the box, in the slip box, behind other notes that those ideas connected to. And then if they connected a multiple notes, he had a whole system of numbering to help you determine where those processes were. The book was just kind of a jumping off point for me to figure out what was going on with it. i did some research on a zetel costin castin, i think is how you say that, which is kind of the name that's been attributed to this whole process.