I’ve seen a lot of confusion regarding the new node so let’s clarify:
All you need to do is collect the 4 OG sets of your class (basically every other set than Haedrig’s gift) and go to the tome in Leoric’s Manor.
Once you have any of them equipped , a page will drop when you click the tome. You can get all 4 pages for your class in a single game, just equip a different set and click the tome again.
RoRG works, you can use it with 5 pieces.
YOU DONT HAVE TO DO ANY SET DUNGEONS. Just collect the sets.
Here’s wudi explaining it too
Later edit:
You need 4 pages of the same class that means you need 4 sets FROM THE SAME CLASS. Getting different pages on different classes most likely wont work.
Bottom line is: Save at least 5 pieces of each set until you pass this node.