Once you have trained an army, you may be wondering how to fight.
First, get familiar with the Unit Movement screen.
Finding a suitable targetEdit
Inactive players can be a good starting point. It is worth bearing in mind that the different colors on the map indicate cities' power in Influence Points relative to yours. Also take note of the various troop structures present in a city as these indicate what type of troop could be defending. For example, if there is a level 5 Barrack, you could be up against Hoplites. You can also click on Towers to view their range. Pick a specific building to attack, try to pick one that isn't protected by too many other buildings (they all have attack, though basements will not currently join battles).
Once you have figured out where you are going to attack, send the attack via the Unit Movement screen.
When selecting the attack, there will be a radius displayed in green squares. This is based off of the total IP of the city that you are sending the attack from. If this radius crosses the radius of any tower, that tower will also be aggro'd into the battle.
When your army arrives at destination it will enter a battle. If another player is already fighting in the same city, you will join their battle. While the fight is going on you can select a building currently being attacked and click View Battle to get a real time report of what is happening (note that you have to have participated in the battle for at least 5 rounds before you can view it). Battles can be very lengthy though, so you may want to just let it run its course and wait for the Battle Report at the end. If some of your troops survive they will bring back loot, a tasty selection of your enemy's resources.
For detailed information on what actually happens during a battle and how units act, see Zechnophobe's Combat Tutorial (Tribal Hero forum).
There is a list of Units here.
Some units and structures such as Archer and Tower have a splash attack rating greater than 1. This means that they can attack as many stacks at a time as their rating. If they cannot reach that many targets any left over splash attacks will not be used. Spike Barricade adds splash attacks to all structures in a city, while Hanzo Formation reduces splash damage taken for select units.
Based on how many more units one side has over the other, there's a chance that your attacks will 'miss' the opponent. A 'miss' does 50% less damage than a hit. The pseudo-code:
delta = max( 0 , attackUpkeep / defenderUpkeep)
effectiveness = attackUpkeep > 200 ? 1 : attackerUpkeep / 200 (basically, if you hit with less than 200 upkeep, miss chance effectiveness will be reduced)...
if (delta < 1) return(0);
else if (delta < 1.25) return(10 * effectiveness);
else if (delta < 1.5) return (17 * effectiveness);
else if (delta < 2) return (22 * effectiveness);
else if (delta < 3.5) return (30 * effectiveness);
else if (delta < 5) return (40 * effectiveness);
else if (delta < 7) return (48 * effectiveness);
else if (delta < 10) return(55 * effectiveness);
return (60 * effectiveness); // if greater than 10
tl;dr If you have a ton more units, 60% of the time your stack will 'miss'.
Battle Attack IntervalEdit
The time between each stack's attack will depend on how many stacks of troops are involved in the battle. Here is the algorithm that determines it:
numStacks = total number of stacks in the battle (combine attack and defense)
adjustedTime = 20 seconds * 100 / (100 + Minimum(400,numStacks))
attackInverval = Max(4,adjustedTime)
In non-code terms, if you only have 1 stack, the attack interval will be close to 20 seconds. At 100 stacks, the attack interval will be 10 seconds. This continues to a minimum of 4 seconds between attacks when you have 400 stacks of troops in the battle.