While there are certain aspects to storytelling that are universal, telling a story is largely varied depending on the medium in question. Even the act of writing and constructing a story is different. With a novel, the process is fairly straightforward as words needs to be put down on a page. But writers can cheat with other mediums when their work is not being directly viewed by the audience. In a screenplay, for example, a writer can first tackle all of the dialogue before going back and separating it based on action. A similar thing can happen with comics, but since comics is a static medium, dialogue has to be separated even further into panels rather than have it become a free-flowing scene. In this regard, creating a comic script can be viewed like a puzzle.
When looking at a finished comic script, a reader can plainly see how panels are divided on a page and then dialogue or sound effects are placed within those panels. But that doesn’t necessarily mean that the entire product was constructed in that order. Especially when there is heavy action or dialogue, this all can be created at two separate times on two separate documents. And then, once they are finished, the writer can go back, disassemble both parts, and see how they would all fit together to tell the story on the page in the best way possible.
This is a complicated process that can constantly change even while the book itself is in production. The writer and artist can constantly have a back-and-forth on how the various puzzle pieces can fit together. Sometimes dialogue doesn’t work in one panel and that piece of the puzzle can go somewhere else. Likewise, if two pieces aren’t fitting together then another one can be created to go in between them. Comics, more so than film or prose, fits the analogy of a puzzle, and sometimes it’s easier for a creator to view a story that way rather than trying to force its creation chronologically from beginning to end.