Unless noted otherwise, all models are assumed to be carrying a hand weapon of some kind. The term 'hand weapon' is used to describe any weapon held in one hand and not otherwise covered by the rules. As such it includes swords, axes, clubs, maces, etc.
Hand weapons have the advantage that they can be used with a shield or another hand weapon, as described below. In both instances, these rules only apply to warriors fighting on foot and not to cavalry and warriors mounted on monsters or chariots.
Fighting with Two Hand Weapons (Infantry)
Some warriors carry two hand weapons, one in each hand, and can rain down even more blows on their enemy. This could include a sword in each hand, an axe and sword, or any combination of hand weapons.
If a warrior on foot fights with a hand weapon in each hand, he receives + 1 extra Attack to account for his second weapon. Eg, if the warrior's Attack characteristic is 1, he fights with 2 Attacks, if his Attack characteristic is 2, he fights with 3 Attacks, and so on.
Fighting with Hand Weapon and Shield (Infantry)
Some warriors carry a hand weapon in one hand and a shield in the other, to easier deflect blows with either shield or hand weapon.
If a warrior on foot fights with a hand weapon and shield, he may increase his armour save by a further +1 in close combat against enemies fighting from his front. So, for example, if he has a shield, light armour and a sword, his armour save is increased from 5+ to 4+ when fighting in close combat.
This only applies in close combat, not against wounds suffered from shooting, magic, or other means.
Also, this only applies against opponents engaged to the model's front, not against foes fighting in the model's flank or rear.