Advice for fighting multiple enemies at once

I found this in the official manual on the official forums:

Line Infantry

Line infantry was the most common Infantry type in the Napolenic wars. Line infantry are usally equipped with a bayoneted musket and sometimes with a small sword referred to as a “butter knife” or “sabre briquet”. Line infantry have medium shooting and melee skills and are a good all rounder troop type.

Light Infantry

Light infantry are light and fast moving units that possess good shooting skills. Light Infantry is equipped with an unbayoneted musket and a small sword for melee combat. Due to their good speed and accuracy; they are especially useful for flanking enemy lines and supporting fire. However, light infantry is at a disadvantage in melee and should thus avoid getting to close to enemy lines.

Riflemen and Jaegers

Riflemen are light and fast moving units with good shooting skills. Riflemen are equipped with a highly accurate but slow to reload rifle and a small sword for melee combat.
Due to their high shooting and running skills, riflemen are especially useful for sniping enemy officers. However, Riflemen are at a strong disadvantage in melee combat and should avoid getting close to enemy lines.

The maximum amount of troops on the battlefield is determined by a setting in the options menu, with a maximum of 150 total. the ratio of troops on either side is determined by the total amount in both armies and the relative tactics stat of both.

For instance, with 200 solders, fighting a group of 100, with even tactics scores you would get 100 men on the battlefield and they would get 50. fighting a thousand, you would get 30 or so to their 120. Once the ratio has been changed, (by death) then each side gets reinforcements at gradually slowing intervals until the unused fighters are used up. If an army is entirely defeated before the reinforcements arrive again, another battle is fought, until one of the armies is exhausted.