This scene command can be used in a number of ways to rename the current selection in the scene hierarchy.
With a number of duplicates, for example Spheres, these can be renamed and given an index. This will obviously be useful to save time if you have a large number of duplicates in the scene and want to rename them. Use the Change All option to rename the entire selection.
Untick the Add Index option to only change the names. When the Auto Index option is ticked the index number will be the one given by Carrara to each object as it is inserted into the scene.
If the objects to rename are mixed in with other objects in the selection fill in the specific name to search for and be sure to uncheck the Change All option.