Not a lot of information about the actual events as they happened; all I've been able to glean are the headlines. The Covenanters are supposed to have run out of ammunition, after what length of time is unknown. Also unknown is whether or not the bridge was barricaded, it seems likely it wasn't.
As far as the game goes, the Covenanters after Turn 3 will roll a D6 for ammo, 1,2,3 means they are out.
The Crown wins if they establish a bridgehead of at least two foot regiments across the bridge. Otherwise the thing could take for ever.
Initial dispositions, the Crown forces are on the left.
The Crown artillery opens up on the Covenanter musketeers, the intention is to push the Highlanders over the bridge and take the fire of the Covenanter artillery while the Crown guns continue to soften up the musketeers.
The Highlanders are on the bridge, supported by dragoons.
Sometime later the Highlanders are in melee with Covenanter civilians who were advanced to meet them. The Crown guns continue to fire on the musketeers.
The Highlanders are in trouble. This would seem an opportune moment to explain the hit registration. Each unit (foot battalion, cavalry regiment or independent unit) has three dice; green D6, yellow D6 and red D6, an easy way of marking severity of damage and only have one die on the table per unit (red D6 the unit is destroyed).
The Highlanders are destroyed and the Covenanters are out of ammunition,
The Covenanter musketeers withdraw and are replaced by more civilians. More Crown foot are crossing the bridge with dragoons behind while the first across fire volleys at the civvies..
With the Covenanter unit to their front destroyed, the Crown foot move forward into line.
This allows a second battalion to form up behind the first, the Crown dragoons are now able to get over the bridge. Declared a Crown victory at this point.