I didn't find an answer to this in the tutorial

How do I create chapters in fiction Novel with parts project? Each time I click Add, New Folder it adds the folder as a new Part, it does not nest it with the rest of the Chapters under Part 1. Why?

You needn’t add things flawlessly, as this is a flexible program. All you have to do is click and drag to move items to a different level of indent, or if you find that difficult, you can use keyboard shortcuts to move stuff around. Try adding Ctrl to the arrow keys while selecting the new folder.

But in time you’ll get used to where things appear when you make new items. Folders are always created as siblings, instead of indented beneath what you have selected. So if your folder is empty and you want to make a nested folder, just create it and then hit Ctrl-RightArrow to indent it. Now if you make folders off of that indented folder, they will be siblings, and thus “chapters” to the “part” folder.

I would just add one comment to what AmberV said.

If you’re going to try nesting documents and folders using the keyboard, you might consider customizing the keys that perform the operations.

In Scrivener, by default, Ctrl-Right will indent, and Ctrl-Left will outdent. A potential issue with those defaults is that in most programs, including Scrivener itself, Ctrl-Left and Ctrl-Right are used to navigate left and right, one word at a time, and together are one of the most common things you can do in a text app (even right here in the browser window I’m typing this post in) other than actually typing text.

In Scrivener, because it’s so common to go back and forth from working directly on text in the editor to working on documents in the Binder, if you don’t keep track of which panel has the focus, there is a risk that you’ll end up changing the binder structure when what you intend to do is move the cursor left or right by some number of words.

Maybe it was just me, but I found that risk to be quite high, especially since I also found keeping scrupulous track of panel focus beyond my mental abilities. For that reason, reprogramming the indent and outdent shortcut keys was one of the first things I did once I decided to start using Scrivener for real (more or less exactly one year ago this week!)

There are other examples of similar – if I"m not mistaken, the defaults for moving items up and down in the binder are almost universally used in other apps to navigate up and down by paragraph – but these out-of-box defaults particularly stand out, as binder structure is one of the last places you want to foul up. (I find myself regularly pressing the up, down, pgup, and pgdn keys, thinking I’m in the editor when the focus is on the binder, which then changes the editor’s content. That’s frustrating, but it doesn’t change project content in any way.)

FWIW, I changed my binder L/R/U/D defaults from Ctrl-Left/Right/Up/Down to Alt-Shift-Left/Right/Up/Down, which are easy to remember but much harder to accidentally use, and are of no consequence should you happen to press them while elsewhere than the binder.