Start with a description of the current workflow
We recently did this for Book Dash. We used the 'brown paper' technique: drawing and writing our entire current process of a huge sheet of brown paper stuck on the wall; and forcing ourselves to describe the process as it was now, and not as we wanted it to be. It was surprisingly tough and complex. We'd been told by an experienced facilitator that even for a simple org like ours, it would take four hours. We set aside just two, rushed in parts, and it still took four. When we were done, we had created one of the most valuable documents the org has ever seen.
Which is all to say: this one piece of the process may need more detail here, or a link to more detail on approach and technique.