Normally mods are playable, even if the installer is for Windows.
If that's the case you can use wine to install it.
For that you'll need to install wine and use the exe with it, or you install the mod under Windows.
sudo apt-get install wine
wine [drag and drop the installer exe here]
It's probably just a simple unzipper, so you should be able to target an empty directory inside your home directory, then copy those files correctly to your steam installation. Also make sure you only paste the location of the installer.
A little tip for the installer, if it asks you to choose the correct directory. Go to the steam directory, in /home/[yourname]/Steam/SteamApps/[nameofthegame]
And in this case make sure you're inside the Modules directory and then create a new directory so that your path looks like.