Players sit at the machines they were randomly assigned during tournament registration. When the tournament timer begins, everyone in the session hits the spin reels  button and/or the bonus pop-ups  on their machine and plays for the duration of the countdown.
However, the mechanics of slot machines are often misunderstood, leading to the Gambler's Fallacy. Many people believe that if a machine has not paid out a jackpot in a long time, it is due to hit soon. In reality, each spin of the reels is an independent event, and the odds of winning the jackpot are always the same.