I like this question. I tend to start writing and the characters will always take over. I don’t sit down and write. There is usually a catalyst that pops in my head, a what if question and I start there. Stories need a plot of sorts, a direction in which to go. However, the way I do it is I think of something that would be interesting to read about and then do it myself. I tend to write books I would like to read and go from there.
I have been writing for years and never have I storyboarded anything. On the one hand I don’t want to know what is going to happen. If you plan ahead then any moments of inspiration would have to be shelved for the future. You will discover, as you write, that the characters will take over the story and do things that might not be what you expected.
I know what the opening scene will be and I know what the outcome will more than likely be then I populate that world and go from the beginning to where I think the end might be.