The shock absorber is a very delicate item that is not easy to deal with for the home mechanic unless you have specific equipment and special tools to do it. Probably that's the reason they don't have a manual. You have to deal with a bottle filled with a high pressurized Hydrogen which is not a very easy task, then you must have a spring compressor to remove the spring. Inside you have a lot of shims and valves etc.etc.