The Object Manager is how you organize content into Layers and Groups. Content such as points of interest, 3D-models, vector & GIS data are added to a Layer. Layers in turn, can be be placed inside a Group. Object Manager lets you set properties and behavior of the project, groups, and layers.
When you open Object Manager, you’ll see the two main content groups:
Anything added to the Master group can be set to be turned on/off whereas content in the Background group is always visible.