I do my scripts in a few stages, none of which are strictly, uh, scripts? I guess. But to use the first chapter of my story as an example.
The outline for the first 16 pages looks like this:
Masahiro and Akane meet in the woods
... That's it. That's the entire outline.
Next step is to clarify that outline for myself:
CHAPTER/PART 1
Masahiro finds Akane in the woods (does he kill the last bandit so that Akane sees it, or does he
just step over the corpses? Undecided, though the first one would be kind of impactful; it means that Masa not only FOUND her, but also saved her). He reluctantly brings her along/washes her off in the river and names her. Plant Masa's missing hand, his bitterness/aversion to people/vague quest for SOMETHING/the fact that ”something” has happened. Either 1 overnight stay to end it, OR setting off for/cresting the rise before the town.
... as you can see, it's still pretty vague and full of notes to myself and unresolved questions and parantheses that spiral off into forward slashes and whatnot. At this point, I have no idea how long it's going to be, or whether this is going to take up an entire chapter, of it it will turn out to be only half of a chapter (it turned out to be only half, but you never know).
Then, I take this jumbled mess and try to untangle it into a page-by-page plot breakdown:
Page one: Masahiro walking through the woods.
Page two: He is startled by a bird and sees something off the side of the path.
Page three: He goes to investigate.
Page four: he finds a clearing full of dead people.
Page five: he's attacked by a bandit
... and so on. Then I take that breakdown, and I pick up my pencil and start drawing thumbnails of all the pages, writing the first script of the dialogue below the pages as I go along:
This example is from a oneshot comic, not from Grassblades, but the method is largely the same. I draw a thumbnail of what I want the page to look like, and then add in a bunch of scribbly notes on dialogue below each thumbnail - a lot of the time I also add notes to myself about what all those tiny stick figures are actually doing, so that I don't forget it by the time I sit down to draw the pages.