the details

When the server serves, the shuttlecock must pass over the short service line on the opponents' court or it will count as a fault.
If the score reaches 20-all, then the game continues until one side gains a two point lead (such as 24-22), up to a maximum of 30 points (30-29 is a winning score).
At the start of a match, the shuttlecock is cast and where ever the shuttlecock is pointing that side begins or a coin is tossed. The winners of the coin toss may choose whether to serve or receive first, or they may choose which end of the court they wish to occupy. Their opponents make the remaining choice. In less formal settings, the coin toss is often replaced by hitting a shuttlecock into the air: whichever side the corked end points will be the side that serves first.
In subsequent games, the winners of the previous game serve first. These can also be called rubbers. If one team wins a game they play once more and if they win again they win that match, but if they lose they play one more match to find the winning team. For the first rally of any doubles game, the serving pair may decide who serves and the receiving pair may decide who receives. The players change ends at the start of the second game; if the match reaches a third game, they change ends both at the start of the game and when the leading pair's score reaches 11 points.
The server and receiver must remain within their service courts, without touching the boundary lines, until the server strikes the shuttlecock. The other two players may stand wherever they wish, so long as they do not insight the opposing server or receiver.