Better documentation

[yodigi7]

How do you expand a header? (figured out it was space)
How do you collapse a header?

[yodigi7]

Also, having trouble with only the headers being rendered correctly but nothing else seeming to work (lists, bold)

[umnikos]

How do you expand a header? (figured out it was space)
How do you collapse a header?

These are called "Folds" in Vim.
https://vim.fandom.com/wiki/Folding#Opening_and_closing_folds
You can also expand a header with a left/right arrow key.

Also, having trouble with only the headers being rendered correctly but nothing else seeming to work (lists, bold)

Bold and italic will only work in a terminal emulator that supports it (I'm using Tilda which also doesn't support bold and semi-supports italic). You can also use gvim which supports bold and italic.