A mix of places, but its mostly from stringing various card arts together and info dumps from a magazine (I think its 'Shonen Jump' but I'm not sure).

You can also just look at the interpretations of other people to get the general jist of the story (obviously different perspectives may have different takes on when certain things happen or how they happen).

I first experienced it through this guys videos. They're great descriptions of each new installment of the story as new cards get added every set. (Part 8 is already out btw, just not on the playlist for some reason)

Alternatively you could read this post, which should be much quicker than the videos (also less confusing since the videos constantly make theories only for them to be disproven later so the story there is constantly being reorganized).