A winning hand is composed of 4 sets of Pungs, Kongs / Chows (you don't need a set of each, it can be all Pungs / all Kongs / all Chows / a mix) and a pair.
Three of a kind i.e. three tiles of the same suit and number or three winds or dragons of the same kind (one of each wind or dragon is not a Pung, although there are some specialty hands in which they are incorporated in this way).
In order to Pung a player requires two tiles of a kind already in their hand.
An exposed Pung is completed with the discarded tile from another player – call out Pung and claim the discarded tile, a concealed Pung is formed from tiles all drawn from the wall and is worth more points than the exposed Pung.
Four of a kind, is as with a Pung but with four tiles.
In order to Kong a player requires three tiles of a kind already in their hand.
Exposed and concealed as with Pung.
A Kong is worth more points than a Pung.
A run of three tiles e.g. one, two, three of characters.
In order to Chow a player requires two of the run already in their hand.
A player can only chow the discard from the previous player.
Chows are not worth any points.
Season / Flower
These tiles are not used to form the competed Mah Jong hand.
Some sets have Flowers and some have both Seasons and Flowers.
They are worth four points each.
There is a Season &/ Flower corresponding to each position (North, South, East, West). If you have your own Season / Flower it will count as a double.
A Bouquet is a set of the four Seasons / Flowers and it will count as a double.