If you have the plans, you probably have as much of a building manual that exists. I will try to take a look at my kit soon, but I am not remembering a manual as such. If I recall correctly, the Ki61 Hein plans are much more detailed than the Spitfire plans with some actual instructions on the third sheet. I have those in PDF. PM me with an address that will accept a 1.5MB email and I will send the Hein plans to you.
The best thing for building a decent scale model starting with a Marutaka / Royal kit is to get a couple those "in action" or "in detail" series of books on the plane you are building. If you are not much worried about scale, the old way was described as, glue up all of the blocks and sand off any bits that do not look like the plane.
. Either way, aggressive attention to weight saving while not compromising structure is very important.