I don't... Get it...

So, a multiverse kinda thing happened and earth's collided with one another and the marvel universe is pretty much being reassembled from bits and pieces of each and it creates "battleworld" but... I don't get it... What is the new universe gonna be called? Is it still 616? How will I know what stories are canon and which aren't? And most importantly, once "Battleworld" is initiated, where should I begin reading to be able to make sense of it?

I've tried googling around but I don't get any of this. Could someone explain this new thing Marvel is doing for its comic universe(s) or link me to something which explains everything in excruciating detail?