You can add mods (typically .fifamod files) by clicking the "Import Mods" button or simply dragging and dropping them into the manager window.
You can download the through the following official download portal or direct community download links provided by the development team. Note that newer versions, such as v1.1.7.2, are often required for more recent game titles like FC 24 and FC 25. Installation & Usage Guide Download File FIFA Mod Manager v1.1.0.rar
After downloading the .rar file, use a tool like WinRAR or 7-Zip to extract the contents to a folder on your desktop. You can add mods (typically