When should the first referee check that the court is free from obstacles?

The first referee should check that the court is free from obstacles before warm-ups and at the start of the match to ensure player safety and maintain the integrity of the game. Conducting this check before warm-ups allows any potential hazards to be addressed, providing a safe environment for players to practice and prepare for the match. Additionally, verifying the court's condition at the match start ensures that no foreign objects or issues are present that could interfere with play. This proactive approach minimizes risks of injuries and ensures that the match can proceed smoothly, highlighting the importance of safety in the volleyball setting.