as a non years long player im really confused to what forever actually is?

I saw the forever trailers and stuff and it looked cool but I only started playing WoW off and on during bfa, the lore of the game is why I wanted to play it well that and i found out consoleport was a thing, and now gamepad support is official which is sweet and I hope retail gets it soon, but enough of that.

im confused about forever though because is it like a new timeline "old" wow or will it allow people like me who never experienced the old ways of the game to play it like how it was and go through the original story, if it even had one.

from what I know wouldnt forever have a completely different world layout because wasnt everything blown up in cataclysm?

I mean i can currently just fly to old places and do old quest and do time swappy stuff in midnite, sure my presence basically murders anything around me but it is what it is.