The rule's simple: The one with the highest points wins, but the rule isn't just counting points...
Require: Standard 52-card pack (no jokers), at most 17 players.
The dealer gives each player 3 cards, including themselves if they also play.
When scoring, only the last digit of the sum of card points counts (A = 0; 2—10 = face value; J, Q, K = 10). E.g. [5♦, 4♠, A♥] = 10 => 0; [7♥, 8♣, K♥] = 25 => 5
If all cards of a player are court cards, the player gets "Ba cào!!!" which is the highest possible hand, even higher than 9 points. E.g. [J♥, K♦, K♣] => Ba cào!!!
If there's a draw, the players with highest hands will have another match until there's one player left.
Suits don't matter, 3♠ equals to 3♦.