yWriter 5

It is a great tool for setting up scenes, character sketches, moving things around. It is multi-device too, meaning it can be used on Windows, iOS and Android devices. My biggest bugbear is it has no grammar checker and the spell checker is very clunky. Otherwise, it's really good, especially as it's free.

I like to put together my outline first. I start by outlining the broad strokes, and creating "chapters" in yWriter. Then, for each chapter, I break down and outline the main plot points and create "scenes" for these. Once I have those, I can add scenes for any sub-plot lines, etc. Once I have each of these, I go through each and flesh out the description as much as I feel necessary. That's when I start writing. Generally I write start to finish, but by doing things this way, if I get stuck in a particular scene, I will jump ahead to a different scene, one I can see more clearly, and write there. I love it for that.

Free and an excellent method of keeping track of large projects.