Attacks in close combat work like shots in shooting - each attack that hits have a chance to wound, the wounded model gets a chance to save, and if it fails is (generally) removed as a casualty. Each model in base-to-base contact with an enemy model strikes with the number of Attacks (A) on its characteristics profile. In addition, the following bonus Attacks apply.
+1 Two weapons. Models in base-to-base contact which have an additional close combat weapon or a pistol in each hand have an extra +1 Attack. Models with more than two weapons gain no additional benefit - you only get one extra Attack regardless of whether you have two or more close combat weapons.
+1 Charge. Models in base-to-base contact who launched the close assault that turn (ie, charged) get +1 Attack on their normal profile for that turn, only if they did not fire in the Shooting phase. Models belonging to units which fired in the Shooting phase do not receive the charge bonus.
Exception: Models such as Terminators, Bikes, Dreadnoughts and Walkers, which always count as stationary when firing, always receive the charge bonus whether or not they fire before entering close combat.
Models not touching an enemy, but within 2" of a model from their own unit that is touching an enemy, may make one Attack regardless of their profile, armament or whether they charged.
Designer's note: This is another important change. Under the previous rules there was seldom any good reason not to charge into close combat in order to get the bonus Attack for charging (do it to them before they do it to you). This change means that troops well-armed with guns may be more inclined to stand their ground and shoot, leading to more short-ranged 'firefights'. Units using flamers and other short-ranged weapons must weigh up the benefits of shooting over getting an extra Attack in close combat.