The new Survival Mode adds two new layers of strategy to Skyrim's base game: weather and hunger. Similar to other popular Survival games like Rust, players will need to manage their temperature and hunger to stay alive in the harsh new conditions players are now exposed to.
Players will need to dress in weather appropriate armor or stay around campfires to stay warm in freezing temperature, while managing their food intake to make sure their characters don't starve to death. You can check out Bethesda's new zoned Skyrim map to see where in Skyrim is the coldest or hottest, and how to manage their survival. Also, be sure to avoid freezing water if you want to avoid dying really quickly.
In addition, food management is more complex than just eating to stay alive. You'll have to eat cooked meat or risk getting sick. If your food is good however, and you become "well fed" you'll receive stat bonuses.
Other Survival additions include a new Fatigue feeling that will deplete your magicka meter if you don't sleep, disabled fast travel, diseases from animals, and limited carrying weight for added realism.
Survival Mode is being offered as part of the Creation Club, a new mod marketplace so controversial, some players modded the ads for the store out of Fallout 4. The new Survival Mode is being billed as "free for one week" where players who download it in the one week period can keep it for free. If you download the mod after that one week, it will become a paid mod.
Skyrim's new Survival Mode is currently in PC beta, which you can log into with an opt-in on Steam, while PS4 and Xbox One players can try out the new mode next month.