Don’t become overprotective of your main notes to the point where you stop making them. A main note’s contents can be as simple as an idea and a link to other ideas.

It should feel a bit loose. Such is the nature of bottom-up systems (6.1). There are no “occupied slots,” because there is no prescribed order. Therefore, there is no need to worry about which alphanumeric IDs have already been taken. Choose any alphanumeric ID that adequately establishes a relationship between the two ideas, and add it to the note

Don’t forget fiction. Using a zettelkasten to capture ideas conveyed through fiction is done in the same way you would any other work. But, fiction also makes it possible to engage with ideas in novel ways. Keep an eye out for character behaviors and traits, narrative arcs, scenes, and settings, all of which can be mined for insights.