The player on your left is your target and the player on your right is your enemy (if you’re playing a 2-player game, your opponent is both your target and your enemy).
The objective of the game is to reduce your target to 0 health, at which point they are removed from the game and the next person on your left is your new target. This continues until only one player remains.
If your target is defeated (no matter who defeats them), you get 1 victory point. When only one player remains, they get a victory point and the player with most victory points is declared the winner.