RULES
A game starts with 4 players being dealt 13 cards each. The aim of the game is to get rid of all of your cards, at which point you will gain a number of points equal to the sum of the number of cards that the other players are left with. Players who do not win will get minus the number of cards they have left.

Whoever has the 3 of diamonds goes first (and must play the 3 of diamonds as a single card). The next player must play a higher single card or pass (single cards are ranked firstly by number and then by suit. 3 is the lowest, 2 the highest (3<4<5<6<7<8<9<10<J<Q<K<A<2) and suits are ranked: Diamonds < Clubs < Hearts < Spades, so the 2 of spades is the highest card). This continues until everyone passes or someone plays the 2 of spades, at which point that player then has control. When in control, a player may play any valid 1,2,3,4 or 5 card hand. Subsequent players must play a valid hand of the same number of cards which is higher than the previous hand played. This continues until everyone passes, at which point control is gained again and any valid hand may be played.

Valid 2 card hands: pairs - ranked primarily by number (so 5 5 < 10 10 regardless of suit), and then by suit (pair with highest suit wins, e.g. 10D 10S beats 10C 10H). Again 2 is highest.
Valid 3 card hands: 3 of a kind (e.g. 5D 5H 5C). Suits do not matter. 2 is highest.
Valid 4 card hands: two pair (e.g. 3D 3H KH KS). Only highest pair is important (pairs ranked as with 2 card hands), so e.g. KC KH 4D 4C beats QD QS JH JS. Four of a kind (always higher than two pair)
Valid 5 card hands: Straight (5 numbers in a row). 3 is low and 2 is high (so can have 3 4 5 6 7 and J Q K A 2 but not 2 3 4 5 6 or A 2 3 4 5). Comparison of straights is based on highest number primarily (2 high straight is highest), and then suit secondarily. Flush (5 cards of same suit) - based primarily on number (2 high flush is highest), then on suit. Full house (3 of one number, 2 of another, e.g. 3D 3S 6S 6H 6C). Comparisons based on higher 3 card section, e.g. 3S 3H 10H 10S 10C beats 2S 2H 4C 4H 4S. Straight flush (both a straight and a flush - again based on number primarily and suit secondarily). Straight < Flush < Full House < Straight Flush