The rules of Canasta
Classic Canasta, as Pagat gives it. Four players in two partnerships, partners sitting opposite; or two players on their own. Two packs and four jokers: 108 cards. Eleven cards each (fifteen at a table of two); the rest are the stock, and the top card of it starts the discard pile.
Twos and jokers are wild. Red threes are bonus cards: laid out the moment they are dealt or drawn and replaced from the stock, worth 100 each and 800 for all four, but minus that if your side has made no meld by the end of the hand. Black threes are discards that block the next player from taking the pile, and can be melded only when going out.
Your turn: draw the top of the stock (two cards at a table of two), or take the discard pile; meld if you like; then discard one card. A meld is three or more cards of one rank, with at least two natural cards and no more than three wild cards. Your side has only one meld of a rank. Seven cards make a canasta: 500 for a natural one, 300 for one with a wild card.
Your side's first meld must be worth a minimum by your score at the start of the hand: 50 below 1,500; 90 to 2,995; 120 from 3,000; 15 if you are below zero. Card values count: joker 50; 2 and ace 20; K, Q, J, 10, 9, 8 are 10; 7 to 4 are 5. Bonuses and red threes do not count. With the pile, only its top card and the cards from your hand count.
The pile: you may not take it with a black three or a wild card on top. It is frozen against everybody once a wild card is in it or a red three started it, and against your side until it has melded; then you need two natural cards of the top card's rank in your hand. Otherwise two cards that make a meld with the top card will do (a natural pair, or a natural and a wild card), or the top card matching one of your side's melds. The top card must be melded at once, and you take all the pile.
To go out your side needs a canasta (two at a table of two), then you meld all your cards or all but one and discard that. At a table of four you may ask your partner first, and the answer binds. Going out is worth 100, or 200 if you melded the whole hand at once with no earlier meld by your side.
The hand also ends when the stock is empty and the player to move cannot take the pile. Each side scores its melded cards, canastas and bonuses, less the cards still held by its players. The game goes to the first side to reach 5,000 (or the target chosen) at the end of a hand.