Tears of the Kingdom – Start Confirmed

Nintendo has revealed on their official website how the game will start... and it's as we have already expected:

Link begins his journey on one of the many mysterious floating islands that have suddenly appeared in the skies high above Hyrule. It’s there our hero will have to gain new abilities before returning to the surface world to begin his epic adventure.

The big set of golden sky islands is probably going to the "Great Plateau" of this game, the tutorial area. It's also where most of the gameplay demonstration took place, so it makes sense. Here you will obtain and master the new abilities – Ascend, Ultrahand, and Fuse (I'm still thinking that Recall will be handled differently) – before getting a new Paraglider somehow and returning to the surface.

 

Timeline of Events?

Now, throughout the game you will learn what happened since the end of Breath of the Wild and the beginning of this game, where in the very least a couple of months have passed. Of course Riju and Tulin have grown quite a lot, but Rito have short lives (ironically the opposite of the Zora) and Gerudo grow quite tall, so this doesn't mean that years have passed necessarily. But there is a period of time where Link has been unavailable to recover from his Malice injury.

Since I believe that this game will mirror the story of Ocarina of Time in multiple ways, it adds up with the theory that the golden sky islands are supposed to be the Sacred Realm. He was resting inside the Sacred Realm, while Ganondorf went and did evil things all over Hyrule.

Now either you will find memories again or there is some other mechanic in place, but many of the things that we saw in all five trailers are probably from visions of the past that you encounter, just like in Breath of the Wild.

• There is a scene in the newest trailer where Link draws the Master Sword from its pedestal in Korok Forest. His hand is not dark here, where this is probably the start of their journey. But he still carried the sword at the end of Breath of the Wild, where there must be a reason why he put it away.
• At some point most of the Sheikah technology has vanished.
  
• Link and Zelda explore the underground world of Hyrule together. This is what we have seen in the first trailer and where they encounter the sealed Ganondorf, who then breaks out of his seal, destroys the Master Sword and Link's right arm with his Malice. Zelda falls into some void and Link can't catch her, but he gets saved by the mysterious hand, which has sealed Ganondorf up until now.
• The "Upheaval" happens, where many landmasses and structures in Hyrule are taken into the sky, including Hyrule Castle.
  
• Ganondorf starts his new reign over Hyrule by taking over Hyrule Castle. He also summons new monsters all over Hyrule.
• Zelda is in the care of the mysterious Zonai character, where he explains the situation to her and they prepare things for Link's awakening. Some of this is happening near the Great Plateau, on some sort of new temple.
• The mysterious Zonai figure restores Link right arm, making him part Zonai, but this is what lets him use the green Zonai magic.
  

The Zonai may also give us flashbacks to the very distant past, long before the battles against Calamity Ganon, where they could show us how Ganondorf was sealed the last time. Perhaps the "Hylia" we briefly see in the final trailer could be the Zelda from that era, and we may even get to see all of the Seven Sages from that time.