I think you would have to be way more specific in terms of time period, and what local. Different armies at different times fought differently.

For instance, if you go back to A couple hundred years BCE you might have Northern European tribes basically charging en masse with shields and spears, axes or swords. Their style of conflict would be more like a bunch of one one fights. Each warrior seeking personal glory, etc. not to say they did not use tactics, they did, but this would be the fighting style.

At the same time you had Greek armies using the phalanx formation. This would be tightly packed, highly organized armies marching shoulder to shoulder. They would effectively creat a shield wall with spears sticking out. Such armies had to be highly, disciplined, if the broke rank you could get the entire army killed. A deadly formation when you keep the enemy in front of you but if you got flanked, or the line broke, you were dead.

Then you had the Romans who were developing a new type of unit called the mandible, sometimes called a jointed phalanx. Also highly disciplined, but more mobile and flexible than the phalanx and more able to react to flanking maneuvers.

So that's just one time period, and one area general area of the world.