Extract from Richard Kane

A New System of Military Discipline
This information might help give an insight into the organisation of the late 17th early 18thc. For the purposes of Charge! one could use divisions instead of Young's 'Company' which was never a battlefield formation anyway. Ive made bold the crux of the piece.
There is not yet any method found to train up our infantry for action in the field otherwise than by representing one battalion engaging another. I shall therefore lay down the best method I can for that purpose. In order to which, I must first suppose our battalion to consist of 800 or 1,000 men. Let us suppose our battalion drawn up with the army on the field of battle, three deep, their bayonets fixed on their muzzles, the grenadiers divided on the flanks, the officers ranged in the front; and the Colonel or, in his absence, the Lieutenant-Colonel (who, I suppose, fights the battalion) on foot, with his sword drawn in his hand, about eight or ten paces in the front, opposite the centre, with an expert Drum by him. He should appear with a cheerful countenance, never in a hurry, or by any means ruffled, and to deliver his orders with great calmness and presence of mind.
The first thing the Colonel should do is to order the Major and Adjutant to divide the battalion into four grand divisions, which is to be the ground-work of all our performances, of which our Martinet (drill master) gives but a faint idea. I find he knows very little of the consequences attending our grand divisions; for from them we form our platoons, our sub-divisions in all our marchings; and from them we form the Hollow Square, as well standing as marching; and that after a much more commodious and readier way than the round-about way now practised; for each of our grand divisions make a front of the square, so that in marching out there, there is no further occasion for square-marking out the ground; and the officers of the platoons may at once know what firing they’ll be off in the square, as well as in the battalion; which will save time and trouble. When pikes were in use, our battalions were composed but of three grand divisions, viz. one of pikes in the centre, and a division of musketeers on the right and left of them; but since pikes have been laid aside, a battalion cannot be disposed for action, but by dividing it into four grand divisions. Our battalions thus divided, and each division distinguished by the:
1 and 2 = the Right
3 and 4 = the Left

Each division to be divided in four platoons which, with the Grenadiers, will make up eighteen; but when our infantry is on the low establishment, as in time of peace, our grand divisions will admit but of three platoons to each, and those but small.
The eighteen platoons are to be divided into three firings, so that there will be six in each. And as it is absolutely necessary to have a fire in reserve, the front rank is to be reserved for that purpose, which on occasion will make a fourth firing; so that the two rear ranks are only to go on with the firings until the commanding officer thinks fit to order the front rank to fire, either by themselves, or to go on with the rear ranks of their platoons, all which depends wholly on the discretion of the officer that fights the battalion.
As the commanding officer will be exposed to the fire of his own men, as well as that of the enemy, he is to take special care that he keep opposite the two centre platoons while the other parts of the battalion keep firing; and he must also take as great care, that when it comes to the turn of the centre platoons to fire, that both he and the drum step aside, and return as soon as they have done, otherwise they must fall by their own fire.
Note, that the front rank of the two centre platoons are to fire with their own platoons, and not to be of the reserve, or fourth fire, otherwise the commanding officer would have no shelter from the fire of the front rank.
Upon dividing the grand divisions into platoons, place a sergeant in the interval of each platoon, after which the Major appoints the officers, and tells them what firing they are of, and how they are to behave; he then acquaints the Lieutenant-Colonel, and remaining part of the officers, that they are to march to the rear when the others take their platoons.
Note that, always upon action, the officers of the platoons are to be posted as near their own companies as they can, without regard to seniority; this being done, the Colonel takes the management of the battalion upon himself.