That's what the instructions are saying, I'd guess. Use the coarsest tool to remove the most material to get them to the point where you use finer grits to remove tool marks and smooth them down to the final shape.
I made a powder horn out of a bison horn that I rough shaped with a coarse rasp then progressively used finer cutting files 'til I could wet sand the finish. 'Course the advantage of rasping was I could shape the walnut end plug and the horn to the same circumference, then smooth them as a unit.