How to get the camera's transform in the currently established room data？

I have scanned and built the room data in quest3. But I don't know how to get the camera's transform in the known room data when starting the application. I got all the OVRSceneAnchors, but I don’t know. That anchor represents the origin of the entire room, so I can’t determine the relative transform of the room and the maincamera.

My development paltform is Unity.