How do i install mods under Linux Mint?

where do i need to make the directory for the mods to be installed ?

I'm using Windows but maybe try look here if this will help : https://hub.coigame.com/Topic/160/-Beginner-Guide-How-to-Install-Mods-in-Captain-of-Industry-\
On Linux Mint, Captain of Industry usually runs through Steam Proton, so the mods folder is inside Proton’s Windows compatibility folder.

The most common location is:

📁 ~/.steam/steam/steamapps/compatdata/1594320/pfx/drive_c/users/steamuser/AppData/Roaming/Captain of Industry/Mods

If the Mods folder does not exist yet, simply create it manually.
If you cannot find the folder, launch the game once first. Proton usually creates the AppData folders after the first launch.

Try that also, hope this helps.

Found it thanks you for your help.