Version 1.4.3:
* New large Sawmill and Fish for Pallets
* New Butchers for Kefir, Butter
* New Slaughterhouse for Bone Meal
* New sugar Factory for Bagasse
* New Production Concrete Factory for Stone
* New Production Fertilizers, Liquid Fertilizers, Seeds
* New Farm Warehouse for Potatoes, Sugarbeet, Woodchips, Sugarcane
Firstly find a mod which you like and want to download. Then download a mod to your PC. Mods are usually in .zip format file. But sometimes it can be in .rar. If a mod file is a .zip format no needed additional actions. If a file is in .rar, then you must unarchive mod with software like WinRar or Zip7. Windows 10 users no need to use software for archives, Win10 itself has a feature to unarchive files.
The next step is to find mods folder in your PC. Usually, it is in Documents/My Games/Farming Simulator 17/2017. Open the "mods" folder and put downloaded .zip archive or unarchived .rar file to this folder.