copy files

I was trying to copy a external hard drive to the mac and clicked on copy which only duplicated all the files on the hard drive. How can I remove the copies without doing each one induvidually.

You can command-click each item you want to select to delete.

How did it name the copies? If they all have "copy" in the name, and that is not part of the original filename of any of the files, you can do a smart folder "search" and collect all the files in one place, select all, and delete them.