Hi! GTMF has 2 stages
operational and tactical(battle)
During the operational phase you can set up your strategy, lines of defence etc. However most people see this as an extra(i.e. not the main attraction of the game), it's a got a square(not hex) map and with limited movements it doesn't quite have the fluidity of a real battlefield. It is much more like a chessboard.
Tactical (battle) - this is what most people are playing this game for. Play area by default is something like 3x3km if I'm not mistaken. In here you can certainly give orders at the beginning and watch it all play out. However I don't think there's any game out there with AI so clever that you wouldn't need to hold it's hand every now and then. Same here - when you begin your battle you give out orders (your plans) according to your assumptions. But your assumptions will most often turn out to be wrong
The tactical battle phase is very fluid and situation changes rapidly. Therefore for best effect you'll have to be ready to give orders when necessary. You've spotted tanks, move infantry out of the way or order them not to shoot and put them in ambush mode. Or you'll need to move your tanks in a new position to cover an approach you missed before.
But by and large most of the planning and ordering can take place during "deployment" and "initial orders" phase. Check what your units can see from which position, set up ambush points and chokepoints. etc. One big drawback during deployment is the limited fixed points (squares) where you can deploy. This is a major pain when deploying MG's and mortars that you want to have right at the edge of a treeline. It's not going to happen unless you get a square like that by chance.
Anyway have a look at youtube for some gameplay videos hopefully that will allow you to gauge what the gameplay is like.