You may want to start with a simple scene you create…
place some simple geometry in the scene.
Create your floor object.
Then create a Collision Material Object that sits on top of the floor that is like a second floor using a different material. This will be the boundary for the camera.
Select your camera and go to the Verge3D settings and select Controls and then choose First Person. Assign your Constraint Material here.
Then give your scene a test.
Thanks, I will give that a try