Has anyone gotten the archeology badge?

I can't seem to find tutorials, even the wiki doesn't have it! I think I've found the "castle" to place the skulls on, but what skulls? I also tried to place dead cultists there, bit nothing… Killing mammoths and boars also never give anything special… I expected to find some sign giving me tips on what to do, but it was nowhere to be found. I would love for someone to give me a tip on what to look for, since I've been trying to spend the least amount of time in the Jungle because I genuinely dislike it, I just want my badgee