> How would you go about storing notes from a book/course so that they fit in this system?
Overall, they don't. Zettelkasten is just one of the folders within my note-taking app (Obsidian), and notes from books go into a separate folder. If there are some titbits that I see being useful outside of the book, I duplicate it into a zettelkasten note.
> Group them together somehow?
I have an "also see" section in my template where I link every other short note that's somehow connected. That's what I meant by "linking them as much as possible". The end goal is to be able to follow the links between similar notes instead of having to search for them. My library isn't big enough at the moment, but once it becomes, I should be able to click on a random note, follow a few links, and have an entire article with sources to back it up with little to no effort, using thoughts I had months or years ago.
> Have an "index" note with just hyperlinks to the rest?
Yeah I also do this. I have a note titled "00 zk" that's an index note for all the zettelkasten notes. I don't fill it out automatically at the moment, but I have a plugin that can do "link all notes within this folder", and I trigger it with a hotkey from time to time. That index note helps me to see similar notes and interlink them, because I never view that folder with a file explorer.
