The Restore Manager supports three restore modes:
Merge, No overwrite - Only old files that are not currently present in the folder will be restored, and no existing files will be overwritten.
Merge, Overwrite - Old files that are not currently present in the folder will be restored, and files that exist both in the backup and in your account will be overwritten with the backup copies.
Delete, Overwrite -  The existing files in the folder will be deleted, and you will get an exact complete restore from the backup.