OK. Some of you may have previously read my theories of "Legend of Zelda: Ocarina of Time" also stating how "Twilight Princess" eventually came to be.
Now I will explain my theories about the connection between "Ocarina of Time" and "Skyward Sword".
"Skyward Sword" is actually the first Zelda story in the timeline, thus taking place before "Ocarina of Time."
There is a possibility that the surface in "Skyward Sword" was Hyrule before it was given it's name.
Many generations of Link and Zelda followed after those events most likely named after the originals or an earlier member of the families.
The Lava Mountain most likely became Death Mountain in "Ocarina of Time".
But where would Kakariko Village be?
As for the term "Hylian". It's most likely a word the people of Hyrule use instead of "Human". Not to refer to someone who is from Hyrule. As Hyrule was named after the race and not the other way around. The word "Hylian" most likely came from Zelda's Goddess name "Hylia".
It is also believed that Hylia was where Lake Hylia in "Ocarina of Time" got it's name.
I also have reason to believe that the Sealed Temple, know as the Temple of Hylia in the past, eventually became the Temple of Time in "Ocarina of Time".
Yes, I know there is a Temple of Time in the Desert in "Skyward Sword". But that has to be a different Temple of Time as it is not shaped the same as Ocarina of Time's Temple of Time.
The Sealed Grounds possible became the Castle Town of Hyrule Castle. But what happened to the Goddess Temple?
It most likely was either demolished or made into something else.
But we can't say that it was made into something else since there is nothing in front of the Temple of Time in Ocarina of Time.
The Link and Zelda of Skyward Sword possibly started building Hyrule Castle.
Zelda possible became the first ever, Queen of Hyrule letting the existence of her descendent of the same name in "Ocarina of Time." come to be.
The Faron Woods possible became Kokiri Forst. Faron's Domain possible became Zora's Domain.
And Lanayru Desert possible became the Gerudo Desert.
As for Demise, it is most likely that he is an ancestor of Ganondorf. Since they have simulair appearances.
Thus, Demise is the very first Ganondorf in existence even if not being named that.
For the door to the side in the Sealed Temple, it possible disappeared as it became the Temple of Time. As well as the space to the left where the tree grew disappeared as well.
So those are my theories about Skyward Sword and it's connection to Ocarina of Time.