This is a scene set up by a community member in JanusVR’s Vesta hosting service, and shared here using the Vesta “embed” mechanism.
You can visit the scene on your screen by pressing the play button in the middle of it. Use the WASD keys and mouse to get around.
To see the scene full screen, click the “Popout” button in the top right.
If you want to use your VR HMD, then attach it to your computer, click on the WebVR icon that appears, and then put on your HMD.
If you click the JanusVR button in the top right, you’ll go into the native JanusVR environment/editor, or to the installer if you don’t have it installed yet.