How do I copy or delete files on External Hard Disk
How do I copy or delete files from an External Hard Disk
MacBook Air, OS X Mavericks (10.9.2)
How do I copy or delete files from an External Hard Disk
MacBook Air, OS X Mavericks (10.9.2)
Exactly the same way as you would on an internal drive.
Select a file, press delete, or copy.
I'm only guessing because your question seems rather strange, but did you use that external drive with Windows? If so, it might be NTFS format which OS X can only Read, not write.
How do I copy or delete files on External Hard Disk