Written Steps(Credit Shared between -Paradox-, TTG_PACK-a-PUNCH, and Cod Wiki)
The meteorite on top of the temple.
At the starting room, there are four dials each on their own wall by Quick Revive. When all four players press ‘X’ at the same time, the moon will eclipse the sun, and a large meteorite will appear on the top of the temple.
Near the MPL, there appear to be two characters locked in the locked area behind the weapon. They want the players to set them free, similar to the Original Characters Trapped easter egg. After they finish their dialogue, magical plates can be found scattered all over the map if you did it right.
These magical plates are a puzzle, they have symbols on it when you stand on them. And you have to match that symbol to another one on the map. To complete this step, it seems as if you have to make all the plates disappear. If you get a few wrong some of the plates will come back. The plates are located on both sides of the long wooden bridge, and by the button that you just pushed to talk to the man who is trapped, but any other spots are unknown. There is also a time limit of approximately 4-5 minutes until the eclipse ends, resetting all progress.
The following are known symbols to appear on the tiles:
A Female gender symbol.
3 Short straight lines intersected by a long straight line.
A Diamond outline.
A Circle with a straight line cutting it in half.
A Circle with a small dot in the middle.
3 Dots arranged in a triangle.
A Triangle outline.
Three players stand on the pressure plate one goes down the water slide and there is a switch there when you down it hold x to hit the switch and that will do it
Go to the waterfall, there should be a diamond on top of the waterfall, shoot it with a Ray Gun. When it’s on the ground, shoot it with the 31-79 JGb215, it should shrink. Knife it and it goes into the slide to the water sprout. Launch yourself with the diamond on the water sprout and it should land on a tower. A new diamond should spawn, that means you did it right.
Go to the underground tunnel near step 2, find a red wheel attached to a pipe and press X. The British guy should say something about the walls closing in.
Walk with a Napalm Zombie next to the gas pipes, it will be set on fire. Once you walk the Zombie through all gas pipes, go back to the rocks and you will here the two people talking about trying to get out of Shangri-La *when all pipes are lit you need to double back to the valve and hit the lever beside
You have to activate the eclipse for this step. In the tunnel with the MP5k on a board, there are now 4 holes on the side of the tunnel. You have to plug these holes using Spikemores. The best way is to lure crawlers towards the tunnels and place the Spikemore facing the holes, so that the Punji spikes get lodged into the holes. After this is done, you have to go to the bottom of the waterfall. On one side of the boulder in the center, there is a brick wall, with a brick sticking out saying “Do not hold X”. Hold “X” and the eclipse will end on its own, signifing that you have completed this step succesfully. Also, a new diamond will appear above the mudpit temple.
There appears to be more symbols on the walls. Apparently there are 13 symbols and you must knife them and they will light up once you get all of them you go to the radio on the table beside the mine cart and listen to it.once you listen to it look far left and you will see it. Now you must turn on the eclipse and activate the glyphs. Now throw a monkey/explosive at the trap and it should work
~Credit goes to KlutchMclovin for steps 10-12
You have to walk to the mudpit temple. If you are walking from spawn the first on your right switch to 1. The first one on your left switch to 3. Walk forward and move it to 4. Move right again and you have to move that one to 16 the symbol looks Cl-. It has a c a lowercase l with a dash connected to the l.
After the previous step, in the present, by the right side of the stairs leading up to the Pack-a-Punch Machine, on the floor by the statue you will find a radio. This tells you that Brock lost his bag of Dynamite somewhere while being chased by zombies. You have to find the bag of Dynamite.
Once you have the dynamite, activate the gongs at night, and then shoot the pole above the mud temple with the upgraded 31-79 JGb215, this will make the meteorite shrink.
~Credit goes to StevieRox for the final step and a more detailed TuT as well as video.
After the last step, go up the Pack-a-Punch Machine, go past where it should be. The player will find a hole in the wall as far back as they can go. Put the dynamite through the hole, and step back. Once the wall has blown, retrieve the Focusing Stone. The player who takes it will receive all seven perks at once. These perks are also permanent and persist through being downed. The easter egg is now over.
A more detailed TuT: http://callofduty.wikia.com/wiki/Shangri-La_Eclipse_Easter_Egg