In the original Timeline picture
Ocarina of Time serves as 3 way split where Link after defeating Ganon in the future. One Timeline appears where he's sent to the past and warns child Zelda of potential events and creates a new timeline where Ganon never rose to power. Another timeline is created when Adult Zelda is left alone after sending Adult Link to the past, and is set after the events of Ganon rising to power. The third timeline, which I originally couldn't accept, is when Ganon kills Link and is never stopped which leads to the events of A Link to the Past.
The official timeline can't function in one universe because Link can't defeat Ganon and die against him at the same time, as two of the timelines are dependent on him winning. The Child Timeline, and The Adult Timeline run parallel with each other in one universe as a result of time travel, and the timeline of Link dying against Ganon is its own universe creating the Zelda Multiverse.