It usually works like this: a military council discusses strategies for the war, the general decides what to do in the grand scheme of things (e.g. which regions to target or a vague looting run), the marshal decides how to execute this plan (e.g. when to move where, what are the line settings), and the vice-marshal is there in case the marshal is wounded or is unable to give the orders (maybe the player is busy with life that day/week.)
There can be variations to this but generally this is how it works. As you can see, it isn't one person doing everything but a team of players. Want to get involved in the process? Make some plans yourself and send them to the realm or military council.
That is the ideal that we wanted back when we said Generals shouldn't send orders to the army. In most realms I have been a part of General dictate every aspect of the war. There may or may not be a council that discuss matters but the General sends out all orders for movement, refit and the like. The marshals only job is formations, pretending you are in a realm that uses them. Otherwise the General orders also include all required line settings.
