In the Conan RPG, armor prevents the character from taking some damage. Armor does not make the character harder to hit as is normal in most d20 and D&D games. The mechanics are simple. I'll show you how it works.
Each weapon in the game is given an Armor Piercing rating. Since the strength of a character is key in that character using a weapon to bash through armor, a character's STR modifier is added to the weapon's AP rating to get a total penetration value.
For example, Rael, a Vanir raider, has STR 14, which gives him a +1 STR bonus with one handed weapons, no bonus with off-hand weapons, and +1 bonus with two-handed weapons.
Rael is wielding a war spear, which is rated at AP 2. Since the war spear is a two-handed weapon, Rael's total armor piercing capability with this weapon is AP 3.
Each armor piece in the game is rated for its damage reduction. For example, a scale hauberk is rated at DR 9. This means, when the character wearing this armor is struck, the armor will deflect 9 points of damage. Thus, if the total damage is 5 points, then the protected character receives no damage. The weapon connected but was deflected--a glancing blow. If the total damage is 13 points, then 9 points are deflected, and the character wearing the armor takes 4 points of damage.
If the total AP of the weapon equals or exceeds the DR rating of the armor, then the DR rating is halved.
Thus, if Rael uses his war spear and hits an Aesir foe that is wearing a scale hauberk, the war spear will not penetrate the armor. AP 3 is less than DR 9. So, on Rael's hit, the damage throw will look like this:
1d10 weapon damage + 1 STR bonus - 9 Armor Protection, or 1d10 -8.
You can easily see that, using this war spear, Rael will put 0-2 points of damage on his foe with a non-critical hit, and 80% of the time, the damage will be zero.
Now, let's change up the scenario a little bit. Fighting next to Rael is clansman, Moyle. And, Moyle is using a bardiche, which is an AP 5 rated weapon. Moyle's STR bonus is +3, and since the bardiche is a two-handed weapon, the STR bonus is 1.5 times normal (+4), giving Moyle a total armor piercing capability of AP 9 with that weapon.
Moyle's foe is another Aesir warrior, but this one wears Mail Shirt and Brigadine Coat that is rated at DR 8. Since Moyle's total AP 9 exceeds the Aesir's DR 8, the DR rating of the Aesir's armor is halved to DR 4. Thus, any non-critical hit that Moyle makes on his foe will result in this damage:
1d10 + 1d8 weapon damage + 4 STR bonus - 4 Armor Protection, or 2-18 (1d10 + 1d8) damage.