"When the little ones fight, you can be confident that they will empower our people in the future. Although that looks... HEY! Stop hurting your brother!" -Fesye, lapak mother.
The Raw Rules
Nothing too fancy. If you have a battle mat, have the GM place the characters and creatures in their spots. Then roll for turn order. Let each player roll a speed check, with plus or minus one rank for ambush advantage or other tactical advantages.
If you don't have a battle mat, feel free to do combat final fantasy style, with every opponent being a valid target for players, and vice versa.
On a players turn they may move spaces equal to 5 plus their speed rank, and they may make an attack to an enemy in range and line of sight, in either order. A small action may be made (Flipping a switch, changing weapons).
Some attacks consume Mana (Spells) and some even consume Health (Vampiric, usually). Have the player subtract the correct amount from their stat sheet..
Attacks, Shielding, Dodging, and Damage
When you decide to attack, you will roll 3d12 plus an extra d12 for each rank you have in the attacking stat (and bonuses for any applicable skills). Once you roll, take only the highest three dice. You hit the opponent if you roll more than the defender's DC. If you roll 5-9 more than the opponent's DC, the attack does 150% damage. If you get at least 10 more, the attack does double damage. If you get at least 15 more, the attack does triple damage. Then subtract the appropriate armor (Armor or Resistance) for the target's Natural and Equipped armor.
Now the opponent will choose to dodge or defend. To dodge, they must roll a Speed check higher than the attacking stat's DC. If they defend, they must roll a Vitality check (Some shields use strength, because they're heavy) higher than the attacking stat's DC. If they successfully defended, subtract the defender's shield's armor as well as the other armor subtracted before. If they successfully dodged, they take no damage and move one space away from the opponent. If they failed, the attack's damage doubles (after applying armors).
An attack that does negative damage does not heal a character, instead it does 0 damage.
If an attack does multiple hits, each time the defender blocks, they must add 3 to the block DC. (An avali's unarmed strike might require a roll of 16 and then a roll of 19, and so on.) This may mean a third or fourth hit is impossible to block.
You can't be too detailed (yes, you can)
Most GMs I know don't have time to write about every creature on the battlefield. An enemy that can't be found in the (not yet written) enemy guide can be represented simply by just Health, Strength (Or another attacking stat), Speed, maybe Mana, and Perception.
Gee I wish Iceball had enough
Willpower to write an enemy guide.