When attacking an enemy you roll a D20 to see if it hits or not.
The DMG stat increases how much damage a successful blow deals.
When blocking an attack both you and the attacker roll D20s. The higher number wins.
The DEF stat increases how much damage is absorbed by a successful block.
Dodging an Attack
Dodging is done by rolling a D20, D4 and a D6. The D20 decides if its successful, the D6 in what direcion and the D4 how far in meters.
The SPD stat increases your chance of success.
If Both Combatants Attack
Similar to if one Defends. Both players roll D20s and deal the according damage to eachother.
Mad Dashes are used to move quickly around the area during fights and are rolled similarly to dodging. You roll a D4 and declare a direction to see how far you move in that direction. If there is an enemy in the way you roll a D10 (Affected by DMG) to charge through them. If the roll fails you stop there.