You just need to install C2, then download and install the separate NW from this url:
RE: older version - that was part of the installation and installed itself within the C2 folder structure. The new NWjs just installs to a separate folder.
Benefits include much smaller C2 download size, as C2 is updated far more frequently than NW is updated. When NW is updated, just uninstall and install new version.
Anything else, feel free to ask.