There are a total of 242 collectibles
required for this this achievement, placed on all the levels/areas. It should be noted that they CANNOT be attained after completing the main story, so make sure you get them out of the way as you play.
The collectibles are cumulative, so if you restart the game, you will only have to pick up whichever collectibles you've missed.
Feel free to find a full video guide with additional information HERE
You can additionally find Digital Strategy maps HERE
, but some collectibles are shown in the wrong spot, and the maps can be extremely vague.
You can use the following video to start the collectibles video guide: