In every slot you can find the Paytable once you have logged in and launched the game.
On you PC, the Paytable button is usually on the bottom of the screen. On your mobile or tablet, you need to launch the in-game Menu button to see the Paytable.

Once in the paytable screens, you can read the game rules and learn how to trigger the bonus rounds. You can also see the paytable where all the symbols and their pay-outs are displayed, along with the rules for any scatter and wild symbols.