Install software, dont forget to add mep library to archicad 12.
Go to ENGiNE directory, copy "MEP Modeler.apx" to our Archicad
add-ons directory.
default is : ArchiCAD 12\Add-Ons\MEP Modeler\
The MEP (Mechanical/Electrical/Plumbing) Modeler is a new
extension to ArchiCAD?12. Architectural practices and
architectural departments of A/E firms using ArchiCAD can use
MEP Modeler to create, edit or import 3D MEP
networks (ductwork, piping and cable trays) and coordinate
them with the ArchiCAD Virtual Building?