You can import your CAD files and library elements into Halocline Layout.
Then choose between Imported CAD Files (Importiere CAD-Dateien) and Imported Boxitems (Importiere Boxitems) in the following window and upload your desired data. In the next step of the CAD import you can choose between different import options. During the process, Halocline Layout and SteamVR must not be closed.
Your file is now in your library.
If you only need individual parts of your CAD model, you can select them in Halocline Assembly and import them into Layout. You can find instructions here: Export of assemblies and single parts from CAD files