Nintendo of Japan has posted an overview trailer for Mario & Sonic at the Rio 2016 Olympic Games over on its YouTube channel. You can check out the trailer, which provides an overview of the 14 events featured in the game, and explains amiibo functionality, in this video.
It appears that if you tap any of the Mario amiibo– which includes both 30th Anniversary Mario, Gold and Silver Mario, and Dr. Mario in addition to the two basic Mario amiibo– you will be granted access to the amiibo-exclusive Mario League. In this mode, you can use your Mii to compete against various characters from Team Mario in a series of challenges. Successfully completing these events will unlock an amiibo Golden Mario outfit for your Mii, which will give your Mii a leg up against the competition in other events.
Tapping the Sonic amiibo will grant you access to the Sonic League. Just like the Mario League, this league will allow you to use your Mii to compete with various characters from Team Sonic in events. Completing these Sonic League challenges will unlock the amiibo-exclusive Super Sonic outfit for your Mii, which, like the Gold Mario outfit, will power up your Mii to give it an advantage in the competition.
There’s also support for other, non-Mario and Sonic amiibo; tapping any amiibo will grant you Coins and Rings to be used in-game.
Mario & Sonic at the Rio 2016 Olympic Games arrives on Wii U June 24, 2016.