Run the installer and then go to the extracted folder and find the MSI file.
Example
C:\Autodesk\Plant_3D_2019_Object_Enabler_English_Win_64bit_dlm\X64\en-US\PLNT3DOE\PLNT3DOE.msi
INSTALL from MSI
msiexec.exe /i "PLNT3DOE.msi" ALLUSERS=1 /qn /norestart /log output.log
Example
C:\Autodesk\Plant_3D_2019_Object_Enabler_English_Win_64bit_dlm\X64\en-US\PLNT3DOE\PLNT3DOE.msi ALLUSERS=1 /qn /norestart /log output.log
UNINSTALL from MSI
msiexec.exe /x "PLNT3DOE.msi" ALLUSERS=1 /qn /norestart /log output.log
CIVIL3D PDQ
PATH\Civil3d_oe_64bit.exe /install /s
PATH\Civil3d_oe_64bit.exe /uninstall /s