A combat order is a set of instructions that you receive from a superior, and delegate to subordinates. As a leader, it is up to you to select the information from "higher" that you need to delegate down, along with any coordinating instructions and tasks you need your subordinates to know and execute.
I will intorduce this in the "Leadership" Folder, and I will go in depth in the "Combat Orders" folder. You can check it out now, or you can come back to it later.