A lot of people find the spli confusing, so I will explain it to the best of my abilities.
1. When link pulls out the Master Sword, he DOESN'T TIMETRAVEL. He is put into 'hibernation' for 7 years.
2. When he puts it back, he STILL DOESN'T TIME TRAVEL. Well, kinda. But things are 'reverted' to what they were.
3. There's only 1 link [in oot].
4. When he kills Gannon[dorf], he is returned to before he opened the door of time.
--So, here the child timeline starts.
5. HOWEVER, the time where he beat Gannon[dorf] still exists, just that Link is gone.
This is proved in the credits where the people are celebrating Gannon[dorfs] defeat.
-- Adult timeline is where Link is gone and he deafted Gannon.
The rest is very deabatable, and the time-travel stuff is just my opinion, but I hoped i made it as clear as possible.
