I usually start in a notebook for notes, a notepad for a rough outline of what the chapter might be about, then, I move over to Google Doc for organizing, typing everything down, copy + paste, etc.
There are many people online who use Scrivener & other programs, but I find that spending too much time on figuring out a program, experimenting with other tools--might do me more harm than good lol. It would be too distracting.