When using the Predict Engine plug-in, the 3D scene (cameras, geometries, lights, environments) is entirely defined using the Unreal Engine interface :
Actors are created in the Outliner, their Transform component defines their position in the level,
Components are added to the Actors to define their properties : Camera, Light, HDRI Backdrop, Static Mesh (geometries and material assignment).
Predict Engine - being a spectral and polarized rendering engine - requires some additional settings unsupported by Unreal Engine. For these settings, additional components are available to complete the existing ones : UVR Custom Settings, UVR Capture Environment. These components are detailed in the appropriate sections of this documentation.