You saw the following error while attempting to install F/X CAD:
Error: Please install DirectX before installing AutoCAD (year version)
Locate the installer folder on your desktop. This folder's name will start with fxcad. Double-click this folder to open it.
Inside the folder, open the folder named 3rdParty, then open the folder named DirectX.
Double-click the file named DXSETUP.exe to run it.
You can now continue installing F/X CAD.