Sometimes Windows does not automatically guide you to the "HP Reverb G2 Omnicept Edition Setup." The workaround is to manually run "HP Reverb G2 Omnicept Edition Setup." by typing that string into the Windows Start search bar.
This will guide you to pair your controllers as well as to download the Omnicept runtime from the developer's portal hp.io/omnicept/downloads.
To determine which version of the runtime is installed on your system, navigate to Program Files/HP/HP Omnicept/bin/OmniceptRuntime.exe and right click on the .exe to get the Properties>Details.