Tennis scoring works in three layers: points make games, games make sets, and sets make a match.
Points and games
Points go love (zero), 15, 30, 40, then game. At 40-40 the score is deuce, and a player then needs two points in a row to win the game: the first gives them advantage, the second wins it.
Sets
A set goes to the first player to win six games, with a lead of at least two. At 6-6, a tiebreak is usually played, first to seven points by a margin of two.
Matches
Most matches are best of three sets. Men’s singles at the Grand Slams are best of five. On the tour, doubles often use no-ad scoring, where the point at deuce decides the game, and a match tiebreak to 10 points instead of a third set.
