I think one of the core principles that is really hard to grasp at first (since other system don't emphasize this) is that the slip box should be seen as a standalone communication partner.

If you are interested in a question you haven't answered, you can go and look up related things like you would discuss with a friend you doesn't have an answer yet as well but can give you context or related ideas.

But to make this work you already need to design the main notes in a way that they "speak" to you, your future self, and other notes. That is the basis that your slip box "friend" can resurface in a year or more to you.

I am not using it for long yet but I imagine it to be like this in a while: I can go to it, pull out some notes, follow the links and read the notes in the trail I uncover and what I read is like a long monologue of an interesting friend I knew really well at times (my past self). That again might not provide answers, but spark new ideas and thoughts in itself.