To use FreeCAD, you might want to download FreeCAD. It’s available for Windows, Linux, and OS X in 32 or 64-bit varieties. Pick your poison. After downloading and installing, you’ll end up ...

So, FreeCAD is the obvious choice – apart from ... find a similar enough model in KiCad 3D libraries, you might need to download one. Check up with your parts’ manufacturers, for a start ...