For starting basic structure, have had good luck with Plottr. If there’s a complex timeline, Aeon Timeline is pretty handy. And once ready to write, Scrivener.

I’ve tried to discern the context in which you’re asking this question, but based on the OP and their replies, I think it’s not so much about outlining than it is organizing details and thoughts before writing the initial rough draft. I might be wrong and that the OP‌ already knows about what I’d laid down below, but I hope even if it doesn’t help the OP, it might be of help to someone.

Outlining is basically trying to organize your thoughts and all the details mapped out before writing. I assume that all the details are already laid out in one form or the other, and now it’s time to put them into order. What order things would be put into depends on what is being described or being explained.

If I were to describe a house’s interior, I might go from the main door, then proceeding as if I’m physically walking through the house, and then describing objects I encounter as if I’m panning the camera.

If I’m describing a person, I might go with the basic biographical details first, then an overview of their achievements, then personal life. Within each heading, for example, their personal life, I might go chronologically.

If I’m describing a process, I might go with an overview of what the process is for, what are its inputs, steps needed to prepare the inputs for the process, and then the process itself in chronological order. Within each step, I‌ might go into the reasoning behind having to do this step, or why this step must go before (or after) some other step.

If I’m describing an idea, I might go for a general definition first, then go more specific, discussing what makes each specific definition different from the others. I might then go for a quick historical overview of how this idea came into being, what ideas have led to this idea, and the thinkers that have contributed to building up this idea.

That is, there’s a lot of approaches you can use to organize your ideas. You can organize your ideas or details based on location. That is, organizing details spatially, like describing a house’s interior. You can organize your ideas based on time, which came first, which comes next, like describing a process. You can also organize your ideas from most general to the most specific (or vice versa, though starting with the most detailed first might require more concentration on part of the reader). One can use these and any other methods of organization you can think of so long as it makes sense given the context.

How you might organize your ideas or details would depend on what you’re trying to achieve in the first place, and some methods are more suited than others depending on the topic. Lengthier works might even require a mix of these techniques. For example, if I were to describe a city for a D&D campaign, I might describe its layout first, laying out the details as if I were walking through the city. Then, I might describe its government structure from the widest in scope to the narrowest. Is it part of a kingdom? How is the city itself governed? Are there any districts, if so, how are they governed?. I would then give an overview of its history—in chronological order, of course. Any other detail that might be of use (for the DM or the players) can then be listed in order of most prominent or well-known to the least.

Now as a demonstration, I’ll attempt to outline this response:

• Foreword and disclaimer
• Basic overview of outlining
• Examples
  • Describing a house
  • Describing a person
  • Describing a process
  • Describing an idea
• Organizing detail
  • Based on space/location
  • Based on time/chronology
  • Based on generality/specificity
  • Combination of approaches and others
• Demonstration

I first try to think of the broad headings. If I can’t do that yet, I write out dot points of my ideas and see if I can group them.

Next, I start expanding the headings out with as many dot points as I need.

When I want to add more detail to a dot point, I indent that further, or write a sentence/sentences under it.

When I’ve got sentences for everything, I start to remove the scaffolding and group into paragraphs.

Example

Say I want to write a how-to guide to change a car tyre. I initially think of two main things:

Tools required

Procedure

---

Now, let’s add some dot points

Tools required

• Jack
  • What is it?
  • Where to find it?
• Tyre wrench
  • What is it?
• Spare tyre
  • Does your car have one?
  • Differences between spare tyres and normal tyres

Procedure

• Prepare the car
• Prepare the jack
• Jack up the car
• Remove the tyre nuts
• Remove old tyre
• Place new tyre
• Tighten nuts
  • Check tightness
• Lower the car
• Test new tyre

Notes

• Plan to replace spare tyre if used
• What if you have no spare tyre?

Notice how I added a new heading when a thought came to mind?

---

Now I’ll keep adding detail until I’ve got paragraphs.

Tools required

• Jack
  • What is it? A jack is a device you use to raise the car wheel up above the ground so you can change the tyre.
  • Where to find it? You can usually find the car jack in the boot of your car, but check with your vehicle owners manual for specific locations. Your car might not have a jack, in which case you will need to source one from elsewhere.
  • Safety Jacks carry significant weight, so can be unsafe if damaged or not set up properly. Check that your jack isn’t damaged before using it. Moreover, you will need to ensure your jack isn’t on a slippery surface or a surface that could be damaged by it. In that case, you can place a plank of wood under the jack.
• Tyre wrench
  • What is it?
• Spare tyre
  • Does your car have one?
  • Differences between spare tyres and normal tyres

Procedure

• Prepare the car
• Prepare the jack
• Jack up the car
• Remove the tyre nuts
• Remove old tyre
• Place new tyre
• Tighten nuts
  • Check tightness
• Lower the car
• Test new tyre

Notes

• Plan to replace spare tyre if used
• What if you have no spare tyre?

---

Then keep doing this until you’ve finished it! Remember it’s normal to rearrange things as you go.

ok, so I am not writer however I write my own diary. I store it in one giant org file and upload it to my private github repo.

Plug for something like Obsidian here. I recently started a new novel and the ability to divide everything into folders and sections that I can link to within my writing has been invaluable.

If it’s been a while since I referenced a place or event or character, I can write their name and link out to their dedicated page full of info and reference material on them. If I have something I think of on the fly that I want to remember, I can create a new reference page and link to it, or add it to an existing page whenever I need to .

The organization is a game changer. I write chapter by chapter, sometimes bouncing around in the timeline, and stitch everything together as I finalize a section.

If you don’t know where to start and you have a big pile of text, it may be useful to run it through an LLM to summarize key points and suggest an outline. If you have privacy concerns, it can still work if you have an offline and local LLM instance in your computer.