Slot machines operate randomly. There is a Random Number Generator (RNG) inside each machine, which cycles through millions of numbers continuously. The outcome of a spin is automatically determined by the RNG when you hit the spin button. That means it’s impossible to predict whether you’ll win or lose.
Some machines allow you to stop the spinning reels early. That makes no difference. It has no impact on the outcome of the spin – there is nothing you can do to control where the reel stops.
Some slot machines might offer you bonus games. The player can influence the bonus prize amount by interacting with an arcade-style video game. While skill appears to play a factor in the outcome of the bonus prize, it’s actually all down to chance. No matter what a player’s perceived skill level is, the RNG inside each machine determines the outcome: whether a player wins the opportunity to play the bonus game, plus the pre-determined maximum amount available to be won during the bonus game.