Volleyball referee what is the correct sequence when whistling for serve?

In volleyball, the correct sequence for a referee when signaling for a serve begins with the referee raising one arm to indicate that the serving team is ready. Next, they blow the whistle to signal the serve, while simultaneously lowering their arm. After that, the referee should observe the serve and ensure that it follows the rules before continuing to monitor the play. This sequence helps maintain clarity and order during the match.