Basic Explanation of Shuttlecock Sport Rules

R U L E 1 9 : SCORING 

When a team makes a fault, the opponent team should be credited with one point. A team wins the set when it scores 21 points and has at least the advantage of 2 points over the opponent team: if the score is 20:20, the competition should continue until one team wins the set with 2 points advantage.

The team that wins a point gets the right of service except if the score is 20:20. After this the teams serve by turns the team that was receiving at 20:20 having the next service.