I think that's our old_friend_mossy helping out with the great instructions there. Thank you Mossy, even if I'm a little late.
I also found this video:
The video isn't the best quality, and not as helpful as Mossy's instructions for China, but still it shows you where to look if you can recognize the maps.
There's something I don't understand about the "hidden levels" though. Are they just for finding blueprints and stuff. When I've played them I never seem to "complete" the level or even see checkpoints. I just play for what feels like a while, get killed, and then eventually just go back through the Stargate... er... Conduit to Atlantis.
Do you ever get a message that the level is compete? --- We're on top for now! Conduit2FC(36): 3354-2948-5226, (38): 4814-7986-3261