Warhammer 40,000 allows you to fight battles with armies of troops and supporting units of tanks and guns. It is up to you as general of your forces to find the best way to use your vehicles and infantry to achieve victory. The Citadel miniatures used to play Warhammer 40,000 are simply referred to as models in the rules that follow. Each model is an individual playing piece with its own capabilities.
Of course in real warfare soldiers group together to fight in squads, teams, sections, etc – individual warriors do not normally go wandering off on their own for obvious reasons! In Warhammer 40,000 we represent the way that real troops fight by grouping them together into units.
Units of warriors fight in loose groups with gaps between each model. This gives the troopers the freedom to move over difficult terrain quickly, and enables them to take advantage of such things as minor folds in the ground, scrub, and other small features to shelter from enemy fire.
Similarly, artillery batteries consist of the guns and the crew that fire them, vehicle squadrons are made up of a number of light vehicles and so on. The different elements of the unit have to stay together to remain an effective fighting force. This is detailed more fully in the rules that follow.
A unit will usually consist of several infantry models or small vehicles that fight as a group, but it can also be a single, very large and powerful model such as a battle tank, a monstrous alien creature or a heavy gun and its crew. In the rules that follow all of these things are referred to as units.
Units can have very different capabilities so are divided into four types: infantry, vehicles, cavalry and bikes.
IMPORTANT: The basic rules that follow deal with the core rules for infantry. Vehicles, bikes and cavalry get their own specific rules sections later.