As promised, I've had a quick look at how to do a creative story type zettelkasten.
It's mostly a question of remembering the rules:
One thought per card.
Simple not verbose.
Cards should be easily reviewed. Physical cards are easy and a simple digital analogy is likely to make the process easier.
It should be possible to move the cards around.
You need to be able to link them.
Tags can help.
So, what to do?
The answer is simply to record all your ideas, whatever they are, and whether they link in your mind or not. No need for them to be driven by a single project, although the chances are that's how your mind will be focusing when you do it.
An example:
card1 Plot idea. Urchin becomes local hero. #plot
card2 Name Twiglet. Orphan. Small. #char #hero >card1
card3 Friendly inn-keeper. Name Blob #char
card4 Small wooden inn with tables on veranda. The Round House. Owner Blob . #place >card3
card5 Photo of Apron. Cook's apron? #clothing #apron #cook
card6 Name Rosie. Caring cook. #char >card5
card7 Twiglet allowed to collect pots at inn, paid by being allowed to eat any leftovers. #regular event >card3 >card6
card 8 'If he had a horse it would be a shetland with a limp.' #conversation
card9 Rosie has a daughter. #char
card10 Name Rosebud. Very beautiful. #char >card6 >card9
card11 Name Trot. Rosebud's pony. Present from boyfriend. #char #pet >card10
card12 Rich boy Name Bran. Enamoured of Rosebud. #char >card10 >card11
card13 Large substantial land owner. Bran's father. Name Tree. #char >card12
As you can see, this is someone sitting down with a snack bag trying to think of ideas for a new story. Inspiration limited, browsing the web at the same time. Then remembering something they'd heard someone say on a bus but forgotten to write down. It's very static - needs something to drive a bit of movement so they think:
card14 Twiglet moons over Rosebud. #motive >card2 >card10 >card12
But that feels old hat. And Twiglet is too small, so unrealistic. So:
card15 Twiglet moons over Rosebud's pony Trot. #motive >card2 >card10 card11
Better. Then catch a bit of news on the radio:
card16 Epidemic. #event #motive
card 17 Epidemic is traced back to Trot. #event #motive
But it doesn't really fit any imaginable arc. Maybe for the beginning fo the sequel. So add #sequel1
Obviously this is oversimplified, and it's at a very early stage of imagining.
It should be obvious that this facilitates free thinking, switching around later and building complexities, but also that it is slow and cumbersome. As the process continues, cards can have new cards linked with information and description etc.
This is a plotter's zettel.
A pantser probably has less to gain, but could still do one:
card1 Bob
card2 Sue
card3 Bob says to Sue
Card4 Then they
Card5 Karl interrupts
Just writing on cards rather than in a document. I doubt it's worth it, but does allow shuffling later.
If you were writing mostly about dialogue and words, then each card would be dialogue ideas written as they come to mind. Subsequent cards with sharper words.
I've not found many programs on Android that will do this adequately. Trello can. ColorNote allows [[wikilinks]].
Most can't do links. Many don't allow the easy going through and moving that makes the process work.