In a game of Werewolf: The Apocalypse, often abbreviated to just Werewolf or W:tA, you play (here it comes) a
werewolf. You (or rather, your character, but bear with me here) were born with this curse, or perhaps it's a blessing, but you probably didn't know it until you hit
puberty, unless you were born a
Metis (see Breeds, below).
You have many powers unknown to normal human beings. You can change shape into any of five forms: Homid, your human shape; Glabro, a bestial-looking humanoid shape; Crinos, a giant wolf-man (or woman); Hispo, a huge dire-wolf; and Lupus, your normal wolf shape.
You were probably born a human being, but possibly not. If you were born human, your breed is Homid. If you were born a wolf, your breed is Lupus. (Just like the forms) If you were born the product of two werewolves breeding together (which is a big no-no, but more about that later, see Litany) then you are a Metis, which means several things. One, you're either deformed or crazy; two, your natural form is the Crinos form; and three, you're sterile. Your parents were naughty. Tsk tsk...
Werewolves shift at the full moon, right? Not exactly. But your moon sign, or auspice as it's called in W:tA, governs your role in the werewolf pack. New moons are called Ragabash, and their role is to be tricksters and questioners of the ways. Crescent moons are called Theurge, assigned to study and pass on the mystic rites and knowledge. Half-moons go by Philodox, and are the judges of the werewolf pack. Gibbous moons are called Galliard, their roles are oral historian, storyteller and bard. And for the full moon, the warrior and battle leader is the Ahroun.
There's a lot more to it, but I'll leave you to explore the mysteries of passing through the Gauntlet to the Umbra, learning Gifts from spirits, fighting vampires and going up in Rank for later...