Of the four playable armies in Warcraft III and the expansion, The Frozen Throne, the Human army is one of the more simple and straight forward. A large part of this is likely due to the fact that the units and structures use names that are mostly familiar. Build order and unit function is much more intuitive because of this.
Resources and Base Construction
Peasants are the Human workforce. They are responsible for mining gold, harvesting lumber, and constructing buildings. Unlike the Orcish Peons, Peasants excel at working together. Once one begins a building project, you can have several others join in to drastically increase the building speed.
Peons gather gold by the sack, with each sack holding 10. They have to run between the mine and the Town Hall in order to credit the gold. This means that if you want to expand outwards to other bases you’ll have to construct additional Town Halls if you want the gold gathered with any semblance of speed. You may have five Peasants working a single mine at a time. Anymore than that and the extras will simply wait in line outside, and you won’t gain gold any faster.
Similarly to gold, Peasants gather wood in armloads of 10. This can be increased by building a Lumber Mill and purchasing the Improved Lumber Harvesting upgrade. Lumber Mills serve as a drop-off point for Lumber. This can be crucial in long battles because, as your Peasants chop trees for wood, those trees will be used up and disappear. Over time this can result in a clearing, or force your Peasants to travel farther for wood. By building a Lumber Mill closer to the trees being harvested, you drastically increase gathering efficiency. Since wood is in high demand both for structures and units, most players will have 4-6 Peasants harvesting at all times.
In Warcraft III and Warcraft III: The Frozen Throne, structures allow the production of various units and also grant upgrades to units and other structures. In a well balanced army, every structure will be in use, both for producing a vast array of offensive and defensive units, and outfitting them with additional utility. Knowing what units and upgrades each building offers will help you to build a stronger and more efficient army.
You must always start with a town hall. From the Town Hall you can train Peasants to gather wood or gold, and build structures. The Town Hall also serves as an armory in case of attack. If you’re desperate for defenses, you can use the Call to Arms ability to recall all of your Peasants and have them temporarily outfitted for battle. You may upgrade your Town Hall to unlock better upgrades and additional units. The first upgrade turns your Town Hall into a Keep. The second upgrades it to a Castle. The gold and lumber cost increases for each upgrade.
The Lumber Mill is a drop-off point for Lumber, and contains the upgrade to increase the amount of Lumber gathered per trip. Improved Lumber Harvesting requires that you have a Keep. You can further increase gathering efficiency by upgrading your Keep to a Castle and purchasing Advanced Lumber Harvesting.The Lumber Mill also contains the upgrade to increase the armor and hit points of all of your structures, called Improved Masonry (Advanced Masonry is also available as a later upgrade).
The blacksmith is a structure dedicated purely to upgrades. The Blacksmith is also a required structure to train certain units, like Riflemen. It contains upgrades that increase the damage and armor of various units. As you upgrade your Town Hall, more advanced versions of these will become available for purchase.
The Barracks is one of the first structures you should build, as it provides your early attack units: Footmen and Riflemen. Footmen can be trained from the very start, but Riflemen require a Blacksmith. Once you upgrade your Town Hall to a Castle, build a Town Hall and a Lumber Mill, you will also be able to train Knights at the Barracks. The Barracks has the upgrades to teach your Footmen the Defend skill, upgrade Riflemen to Long Rifles, and Animal War Training.
Altar of Kings
The Altar of Kings is where Heroes are born (literally). It is used to summon and resurrect fallen Hero characters. In campaign mode, you will likely start with the only hero or heroes you will get for that mission, and the Altar of Kings will only be used if they are killed. In skirmish battles you can summon multiple heroes of the various types that are available. Note: Only one hero may be summoned at a time, and you cannot “queue up” additional hero summons.
Scout Towers are cheap structures that have no attack abilities. Placing a Scout Tower outside your base offers a little bit of early warning in case of attack. They can also be upgraded. The Guard Tower upgrade gives the Tower a basic arrow attack. The Arcane Tower upgrade gives Scout Towers attacks that are effective against Mana users, like heroes and spellcasters. The Cannon Tower upgrade gives Scout Towers attacks that are most effective against clusters of enemies (requires a Workshop).
The Arcane Sanctum is home to the magical units of the Human army. You can build an Arcane Sanctum once you have upgraded your Town Hall to a Keep. There are three units available from the Arcane Sanctum: Priest, Sorceress, and Spell Breaker. Priests and Sorceresses are available immediately, while Spell Breakers require you to have an Arcane Vault built. There are individual upgrades for each unit available at the Arcane Sanctum. Additionally, the Magic Sentry upgrade is available which allows your Towers to see invisible units.
The Workshop can be constructed once you have upgraded your Town Hall to a keep and build a Blacksmith. The Workshop offers the following units and upgrades for each: Mortar Team, Siege Engine, and Flying Machine. It is also a prerequisite for upgrading Scout Towers to Cannon Towers.
The Gryphon Aviary can be constructed once you have upgraded from Keep to Castle, and constructed a Lumber Mill. At the Gryphon Aviary you can train the Gryphon Rider and Dragonhawk Rider units and upgrades for each.
The Arcane Vault is a structure required to produce Magic Breakers at the Arcane Sanctum. In addition to that, it holds several use items that a hero can purchase and put in his inventory. These items will often come in very useful, especially in the thick of battle.