If a scene is being rendered and you drag-n-drop a .vrmesh or .vrscene file you can choose to Merge the new asset with the currently opened scene or Open the new file.
This example merges a few .vrscene files and adds a .vrmesh file and assigns a material from the scene to the .vrmesh.
In addition, you can rotate, scale and move each object around. First enter the Selection mode by pressing the selection () button (or hotkey Q). Select the object and press W for moving, E for rotation and R for scale. Press the Q key to go back to selection. Use the Esc key to deselect all objects in the scene.
You can also hide/unhide any object from the Objects tab.
The Materials tab can be used to assign any material to the selected object using the Assign to Selection button.