Scoring. Rally scoring: every rally produces a point, regardless of who served. Sets go to 25, win by 2. Most matches are best of three (or best of five at higher levels).
The deciding set goes to 15, win by 2.
Rotations. When a team wins back the serve, all six players rotate one position clockwise. The player who rotates into position 1 (back right) becomes the next server. Players must stay in their rotation order until the ball is served.
Three contacts. Each team has three contacts to get the ball over the net. Typically: pass (or dig), set, attack. Touching the net while the ball is live is a fault.
Reaching over the net to contact the ball before it crosses is also a fault.
What counts as a legal contact. The ball can be played with any part of the body. On the first contact (usually a pass), a momentary contact or slight lift is often allowed, especially at youth levels. Prolonged carries or double contacts (touching the ball twice in one action) are called faults.
Serving. The server must be behind the end line. The serve can be underhand or overhand. The ball must clear the net and land in bounds.
Net serves are legal and in play in most current rule sets.
The libero jersey. The player wearing the contrasting jersey is the libero, a back-row defensive specialist. They can substitute freely but can’t attack the ball from above the net or set from the front zone using overhand finger action.
The thing parents get wrong most often. Thinking the team scored a point when the other team’s ball lands out. That is a point. Also: the rotation. Players can move anywhere once the serve is contacted, but they must be in the correct rotational order at the moment of service.