To install this mod, you will need the following software:

OpenIV: If you're not familiar with OpenIV, take the time to learn about it before modifying your game. Incorrect usage can damage your files. Always make a copy of your files in the "mods" folder before installing any mod.
If you're already familiar with dlcpacks, you probably know how to install this mod. If not, follow the steps below:

Installation Instructions
Open OpenIV and navigate to the following directory:
update/x64/dlcpacks

Place the snowy_mountains folder inside the dlcpacks directory.

Next, we need to declare the DLC in the game. Go to:
update/update.rpf/common/data

Locate the file named dlclist.xml. Open it using a text editor such as Notepad or Notepad++.

Add the following line <Item>dlcpacks:\snowy_mountains\</Item> to the end of the file, just before the closing <Paths> tag:
(Do not include the quotation marks around the line above).

Save the file and close the text editor.

That's it!
Now run your game and enjoy the mod!