The jackpot is triggered by a specific combination of symbols on the reels. When you pull the lever or push the button, the random number generator generates a mixture of symbols. If the given combination matches the jackpot combination, you win big time.
Use the five-spin slot strategy to play up to five spins at various slot machines. It's time to move on to the next machine if you receive non-0 wins. With the five-spin slot strategy, you are simply trying to get a taste of several machines rather than trying to win multiple times on one particular machine.