File Explorer is just for browsing file system which does not support custom ordering unless you add some alphabetically sortable prefix like a number to each filename which is very inflexible.
More proper way to do it is to create new note named e.g. Outline1 and populate it with list of links to each file you want to include.
Suggested order of files ↑ would also need to be stored in some file so this is effectively implementation of this feature. Although there is still a lot of space for automating this via plugins. For example syncing folder content with note content might be desirable.
Edit: one attempt is done here: Folder as markdown note
Now instead of files, you are reordering the links. There are customizable hotkeys to Swap line up/down, set them to Alt+Up and Alt+Down.
This allows you not only to reorder but much more.
You are already seeing pop-up preview of each file by Ctrl+Hover over link.
You can duplicate the outline and create parallel alternative order while still pointing to the same single original instance of each file.
The list can have header and YAML metadata.
Each file can be annotated by adding text around the link and then see comments from all outlines collected in file’s backlinks pane.
You can separate files to groups or indent one under another to create nested list,
Make more important **[[file]]** bold,
Present file by another text than filename using piped syntax [[filename|nice text]]
Each file can be referenced in multiple places within one outline.
…
On this forum, similar files are sometimes refered as “MOC” (Map Of Content).
Obsidian has flexible system of panes that allows to drag opened “Outline” note (icon next to header) into left foldable pane so it behaves almost like the file Explorer. There is also Andy mode plugin
references:
- https://notes.andymatuschak.org/Create_speculative_outlines_while_you_write
- similar discussions:
Nice implementation of multi-level hierarchical notes: https://gingkoapp.com/
What I would miss from it for general note-taking is inability to show one note in multiple places due to hierarchical nature. In Obsidian, it is possible to display content of one note within another via transclusion/embeding syntax ![[filename.md]].