I just got it to work 
I deactivated this plugin:
Apparently it interfered with the other XR plugins, not sure.
Also, SteamVR has to run before opening the Unreal project. Letting it start automatically by opening the project didn’t work either.
Where do I get the most up-to-date demo project for this plugin? I can’t find it anywhere. The videos say it’s in the marketplace description but it’s not.
I am also finding that the Demo Project is no longer in the description on Fab. I was able to track down the 5.4 Demo Project, but if there is a 5.5 version it is seemingly unavailable.
Anyone have the link to the 5.4 Demo Project? Can’t seem to find it.