first of all, choose your preferred combat theater, the army/militia you'd like to simulate, and your enemy army/militia you'll fight against. you must also choose whether it'll be an offensive or defensive operation, and whether or not you wish this to be strictly combat, or a more accurate representation of a soldier's life in your desired theater (i.e having to deal with humidity and mosquitoes on tropical theaters, or dealing with the freezing cold in the winter). you may also alternatively choose a year you wish the simulation to be set on, and you'll be given the accurate equipment of the army you have chosen at that time. oh, and most importantly, have fun.