prefab_to_folder.py is used to converte the prefab. procthor_to_scene.py is used to converte json in procthor to usd. You need to modify the path of the converted raw assets in the import_asset_new() ...
The VRTK directory is where all of the relevant files are kept and this directory can be simply copied over to an existing project. The Examples directory contains useful scenes showing the VR Toolkit ...