>>10389479unless its retold/revised/retconned, you just pretend it happened like before, except there was no earth-1/2/3/4/5/6/7/8/etc
If you followed the comics at the time, it was pretty easy to understand.
They relaunched and/or did storylines for characters in the comics to create a new starting point for readers. These retold their origin and other early superhero careers. So Superman got the aftermentioned Man of Steel book and Batman got a Year One storyline in issues 525-528 in Detective Comics (i don't actually know what issues and comics it came out in). Flash got killed, but they did a tribute issue and had Wally West taking over, recapping his own time as Kid Flash with Barry Flash.
Later on they did Zero Hour event (miniseries) to snip off all the ends that didn't get fixed with CoIE, like killing off the Justice Society of America, because they'd have to be 100 years old by then and Legion of Superheroes got a retelling. Other things happened to clarify the history for Superman/GL/Flash. So almost all the comics got a 0 issue during that event.
The rule of thumb from the 80s and 90s was only shit told after CoIE happened actually happened. Anything that happened before probably didn't happen, and would be brought up or retold if it did. Perfect time to be a comic reader and had some of the most famous stories that are still reprinted today.
In the 00s, they did another reset, and brought back the stuff CoIE destroyed, and made shit confusing again.