Players must battle each other and kill their opponents’ troops to get a score. The score is based on the might of the troop killed.
Check this battle for example.
The defender was able to kill 500x Siege Crossbows while the attacker killed 156x Elven Archers and 500x Elven Militia.
So their scores are as follows:
156x Elven Archers is equivalent to 624 might and 500x Elven Militia to 2000 might. So the attacker received 2,624 points.
While 500x Siege Crossbows is equivalent to 8,000 might. So that’s what the defender received as his score.
Also, since the score is based on unit’s might, units that don’t have might such as Supply Wagons, Supply Caravans and Supply Carts don’t give out points regardless of the number killed.