Entering the temple to acquire Thor's hammer.

1. Gear up (its recommended you are at least moderately geared, and have a high immune system) storage will become very important having a base or a vehicle will help make this journey much easier. Smoke Monster lingers in the dark so watch out.
2. Purple Key Card - The key card can be found at the prison island.
3. Scuba Tanks/ Underwater Tracker - KMUC - The mountain located on the main island is called KMUC, it is a huge military base located at the top. Head there in order to find the Scuba Tanks and the under water tracker. These spawn through out the base, but are guaranteed spawn deep within the facility located in the mountain (the bottom). These tanks can be filled up at almost all gas stations on the map, they each have an air filter that you manually need to turn on. Make sure to shut them off once you've filled your tanks. (You will need a ghillie Suit eventually, these can be created by using burlap sacks and netting...these spawn in the wild or by breaking down ghillie items...and they spawn a lot in KMUC so take advantage) 
4. The Staff - The staff is found randomly at specific diving locations. Each one of these locations will be randomly triggered every restart and you need to use the Underwater Tracker to find where to dive, it is recommended to use a boat. The staff spawns are NOT guaranteed and are random. You might need to hit different diving locations or try multiple days before getting the staff. High level loot spawn in the locations as well, it will be a black chest found underwater (this includes guns, nails, Stag clothing, etc.
5. Smoke Monster [Insert compound name] - You need the smoke monster, nicknamed Smokey on The Network, to appear and you must have the staff in hand in order for you to be teleported to the Temple. In order to encounter Smokey you can do 1 of 2 things:
A) you can wait for him to appear randomly at night and have the staff ready
B) you can head to Sheep Island (also known as bear island or Crater island) located at the bottom right of the map.
Make your way to the center of the Crater itself and climb all the way up the tower located in the middle. It's guarded by a massive amount of zombies so be ready to take them on or sneak by. At the top of the tower you will find [Insert compound name]. This will be a black ball that will be used to summon Smokey. To summon Smokey, throw the Smoke bomb (black ball) far off and hold the staff in your hands quickly. If you don't throw it far enough, it will not trigger properly. Once Smokey stops moving and is just a sphere almost , simply walk into the smoke and wait to be teleported. If you are in party of more people make sure the person with the staff walks into the smoke last.
6. You're at the temple. good luck and make sure you get both handle and the Mjolnir hammer, you need to combine both.
This is NOT the only method to do this, but its the easiest way and one tested on This is NOT the only method to do this, but its the easiest way and one tested on The Network that works with 100% success (provided you live:)).