Check your mail upon logging in to grab the invitation and five coins. You’ll be transported to the Super Adventure Box once you use the invite. Otherwise, you can enter the event through Rata Sum near the Magustan Court waypoint.
Once there, check out World 1 to begin. You should see a happy cloud, a villager, and angry cloud,
“Speak to the happy cloud to enter Infantile Mode. This is the easiest way to experience Super Adventure Box but offers the fewest rewards. Complete this mode by following the rainbow bridges the cloud creates to avoid most puzzle and platforming sections.”
The villager will allow you to play in normal difficulty, while the angry cloud will enter you in Tribulation Mode. The Super Adventure Box gameplay consists of platforming, puzzle solving, and solving challengs.
The event is set to continue until May 12. Good luck and have fun.