How to install mods on Linux

You can install mods on computers without the %appdata% folder directly in the game folder but you must sort them in the correct folders by hand.

Instructions

Download and unzip the mod file as usual.

Open the game folder, you can do that through Steam by right-clicking on the game and then go on "Browse Files". Open the "gameresources" folder.

The creator explicitly states not to put mod folders in the gameresources folder to prevent it from breaking the game.

This is where you have to sort by hand. You must move every file manually from the mod folder into the corresponding folder in gameresources. Be aware of folders inside the folders.

Example: you put a file from your downloaded mod folder from buildings > sprites into buildings > sprites of the game resources folder.

Basically you are adding files manually to the gameresources.