At the start of a combat encounter, characters build their dice pool. The initial size depends on the stat associated with the weapon the character is currently using, and whether the character is proficient with that weapon.
If the test succeeds, the margin of success is added to the weapon proficiency and the attacker rolls that many damage dice -- the dice specified in the weapon description -- and adds their damage stat, if the weapon allows for that. The final sum is subtracted from the defender's \stat{hp}.