I have been backing up folders and files from multiple computers to one external drive. It no doubt has a significant number of folders/files that are no longer of use. Looking at the contents of the N360_Backup folder using file explorer, it is not obvious how to identify what folders are from what computer or from how long ago. The N360_Backup folder has grown very large and I'd like to purge or delete no longer relevant entries.How does one do that?