If you don’t have an AQWorlds account, once you log in and choose a server, you will see a button in the tutorial. You can use that to go straight to the event OR after completing the tutorial, you will land in Battleon. A button on the game menu will take you straight to the event, once it has started.
If you already have an account, once you log in, you will be able to use the button on the game menu to go straight to the event.