What you'll need : Shield, Scavenger, and You will want the Raygun Mark lll's

Step 1 - From the starting area go through the first building. In the upstairs part of the building you'll see a book case. Go up to the book case and find a book you can interact with it will pop up on your screen at standing height. This will open a door to your right by the stairs in the corner. Grab the snow globe in the room. You will not need to use the snow globe anymore until the end
Step 2 - Blue rings will form around the map on the ground 1 at a time. You have to get kills in the circle. The zombies do not have to be in the circle. The first one should be in the building with the snow globe by spawn. These rings are very easy to see and are big. The next one should be on the right side exiting the snow globe building away from spawn. The next area should be by electric cherry. The next location should be at box. I think this is the last location if not continue up the mountain and complete the final blue ring. Once you completed all the rings a key will pop out of the ring you were in. Pick it up
Step 3 - Go to spawn. Behind the Ski lifts you came on, on the wall should be a little red control panel thing that asks you to put in a key for the ski lift. Put the key in. Then go on the ski lift and shoot all the evil snowmen that spawn while riding. You will get a completion chime when you complete it. (If you fail this step just go back down and turn the key in the same place and start again)
Step 4 - After the ski lifts go through the building up on the mountain and you should find a spirit coming from the gondola entrance. Guide this spirit and take it to the grave yard. Also there might be some evil snowmen on the way down that you might have to shoot. I shot some, but was unsure if they contributed to completing the objective(Just follow the spirit and don't die. If you leave the spirit you will have to wait until the round is over to start again)
Step 5 - Go back up to the ski mountain and then ski down a mountain. You will have to ski through the two polls down the mountain. There are many polls to ski through. Once completed a key will spawn when you enter spawn. Grab it. (If you fail just go back up and try again)
Step 6 - (This is where you want a MK lll the most let alone in the spirit guiding step) Take the key up the mountain to the gondola sight. Once you're there you can put the key in If you put it in you will be locked and confined to that space until the gondola arrives so stay alive. Once it arrives you will need to finish the round. Once you finish it a reindeer round should start so just finish the round. If not wait for the reindeer round to start and then finish it.
Step 7 - Once the reindeer step is done you will need 25000 points to buy the gondola which will immediately take you to the boss fight. Make sure you're prepared. Once in the boss fight place the snow globe on the pedestal when your ready to fight and enjoy.

Tips for the boss fight - Shoot the 4 coal buttons on the snow man. Do this each time he respawns them.
The scavenger is buffed in this map so shooting it at the snow man will do damage on all 4. The raygun mklll is very wanted it will protect you from the insane amounts of zombies and reindeer as well as a wall that he summons to put you in a confined space.
When he breathes ice breath on you. You'll get stuck so keep jumping to get out