Teams score a point on every rally, no matter which team is serving. Back in the day, a team could only score a point if they were serving.
Winning the serve back from the opponent is called a side-out.
Matches are played best of 5 sets. The first four sets got to 25, the fifth set goes to 15. The first team to win 3 sets wins. A team must win a set by two points. The set continues until one of the teams reaches a two point advantage.