I’ve thrown away most of my mass battle notes, but I do remember the basics.

Instead of individual characters, units are broken into groups of melee squads and non-melee squads up to 100 pts., commanders, and uniques. Squads start the battle/skirmish with 1 character selected as the leader of the group. This chosen character doesn’t have to be a commander. The squad’s speed is limited to the lowest speed of any piece in the unit. So an E-Web in a group would make the entire squad’s speed 2. Characters in the squad must end their movement within 2 squares of at least one other character in the squad.

When attacking with non-melee, you have 3 choices:

1 attack with one unit that has LoS to the target at an additional +4 for each squad member that also has LoS to the same target; 2 attacks at up to 2 different targets following the same combine fire rules; or Cover Fire - pick a target enemy squad with characters your squad can draw LOS and you roll a d20 for each character the attacking squad can see, up to 3. For each roll of 11+, the chosen enemy squad suffers half of the combined base damage of the attacking squad, divided as the defender sees fit among the targeted squad.

Uniques - unique characters are not part of the build cost of a squad. Instead, uniques can be assigned to the squad during the skirmish and May freely change squads during the game. When not part of a squad, a unique character counts as a s squad for purposes of victory as described below.

Commanders - commander effects are limited to the map on which the character is standing, even when the effect does not normally have a range. Relay Orders ignored this restriction.

Melee characters/squads: Rules for melee are similar to non-melee, with the exception of combat choices. Each character adjacent to an enemy attacks as normal. If at least one character in a squad is adjacent to an enemy with melee, that squad is engaged. Characters in an engaged squad cannot move more than the squad’s base speed and cannot move more than 2 squares away from other squad characters.

Regrouping: During the game, characters in a squad will be defeated. When a squad’s nominated leader is defeated, if any of its squad characters are still in play, those characters each suffer 10 damage ignoring reduction and prevention effects. They may then join another squad whose leader hasn’t been defeated and who is within 12 squares of at least one member. When a squad contains melee and non-melee characters, melee characters may still only attack adjacent enemies.

Winning the game: A player wins by either:
Scoring points equal to the build total; or by defeating more than half of the total squads on the opposing force. So, for example, if a player has 8 squads, they lose the game when at least 5 of those squads are defeated.