Every liester game, every player gets something called role and every role in this game has their goals:
green colored roles: these are good guys in this game, also known as campers. you must kill all the werewolves and the villains. the catch? you dont know who is camper and who is a werewolf
red colored roles: these are bad guys, also known as werewolves. you know who are your teammates and can talk with them during night. the goal for these roles is kill all campers and all villains before they kill you.
as you can see from the above this is where lying comes in to the game. Werewolves will try to act/frame a camper role like Doctor but then backstab them and win the game. whereas camper roles will try to find werewolves by detecting them lie.
Fortunately, every faction in this game has roles that will help them win the game. Campers have roles like sheriff, which can check someone at night to know if they are bad, or Doctor which can save someone from dying by werewolves! but also, werewolves have roles like utilitywolf which has doctor’s heal, gunner’s bullet and a role revealer or disguiserwolf which can change sheriff’s result.
purple colored roles: these are known as Evil roles each purple role has their own win condition for example Mafia member role must be the last one alive to win while Clown role must get lynched to win the game. Basically if you got a purple role and you are evil role then good luck winning the game.