To determine whether hits are scored, roll a D6 for each model fighting. If a model has more than 1 Attack roll a D6 for each Attack.
The dice roll needed to score a hit on your enemy depends upon the Weapon Skills of the attacker and the foe. Compare the Weapon Skill of the attacker with that of his opponent and consult the To Hit chart on page 69 to find the minimum D6 score needed to hit.