Gentleman
There is a lot to understand to get the troops to do what you want, the Doctrine is an essential part of the actions of your command.
As I haven't downloaded the demo myself I dont know if the doctrine is their as yet, (it should be) but if it is you are going to have to tweek it.
Read the manuel and adjust it. Or experiment.
Just have to remember you are controlling bigger units now, instead just giving seperate battalions diferant orders. For you have to look to the deportment of your Corps or Army.
It will take getting used to. Experiment with Cavalry, use the terrain to create surprises. Surprises, can upset the morale of the enemy or of your troops.
Use the Tactical Bombing orders, and Resume and Halt Progression orders, as you see fit.
In the doctrine you will get to chose how to use your Cavalry, to pursuit, or not, do you want your infantry to pursue the enemy, after they run
There is a lot of scope in this.