The shack is located north of Windhelm, not far from Snow Veil Sanctum. You can fast travel to it immediately after installation. There is a cooking station, a bed that gives Well Rested bonus and a bunch of containers. Everything is static so don't worry if you accidentally fus ro dah inside the house.
Installation:
Download and install via Vortex/Nexus Mod Manager or download the archive manually, copy and drop the ESP file into your Data folder and make sure the plugin is activated.
Mods used in screenshots:
Noble Skyrim
SMIM
High Poly Project
Rudy HQ - Miscellaneous
Medieval Spirits
CL's Barrels and Crates
Ruins Clutter Improved
Embers HD
Designs of the Nords
RUGNAROK
PELTAPALOOZA
Rudy ENB
Fluffy Snow