I guess this is the bit that is confusing to me
new continuity does not constitute a full reboot of the DC Universe but rather a "soft reboot". While many characters underwent a reboot or revamp, much of the DC Universe's history remained intact. Many major storylines such as "War of the Green Lanterns", "Batman: A Death in the Family" and Batman: The Killing Joke remain a part of the new continuity, while others have been lost in part or in whole.
So the comics assume you are familiar with certain things that happened in the past, but you have to figure out which things did or did not happen?