What essentials should we pay attention to when playing volleyball?

Volleyball knowledge and rules The length of the court is 18m and the width is 9m. The stadium is divided into two equal fields by the center line, and the center line is set with a net of 9.50m long and 1m wide. The height of men's net is 2.43 meters and that of women's net is 2.24 meters. The ball is made of leather and filled with rubber or similar substances, weighing 260 ~ 280 grams. 19 12 stipulates that athletes from both sides must rotate their positions. 19 17 stipulates that each game 15 points. 19 18 stipulates that each team has 6 people. 1922 stipulates that both sides must hit the ball over the net within 3 times. In the past, a service scoring system was used. 1October 28th, 1998, 18, FIVB decided to change to the scoring system per goal, and it was still the best of five games. The winner is the one who scored 25 points in the first four games, and the winner is the one who scored 15 points in the fifth game. In case of a tie of 24 or 14, the game will continue until the first team leads by 2 points. Competition method 1. Pre-match preparation: First, the referee will preside over the draw, and the right to serve and the court will be selected first. Second, the start and end of the game: the first referee will stand at the end line of his own field after blowing the whistle, and then stand at the original position when blowing the whistle (the position table filled out before the game). Third, scoring: a. After one side serves, the team makes a mistake in receiving the ball, fouls or the ball falls into the opponent's court, that is, the server scores and continues to serve; B. If the server serves illegally or out of bounds, the opponent scores and changes the service. 4. Time-out and substitution: Each team has two time-outs and six substitution opportunities in each game. (It can be required when scoring a dead ball) 1. Time-out: each team has two time-outs in each game; There is a technical pause every 8 minutes in the regular competition. 2. Substitution: A. The main player can only quit the game once. When he takes part in the same game again, he can only return to the game to take his place. B, the substitute can only play once per game, and can replace any main player. The same game can only be replaced by the player he replaces. Note: The player who started the game is the main force, and the other players are substitutes.