How to delete files copied from other WD cloud device

Hi all,

Recently had a disk failure which was annoying. Purchased a duo to give me raid1 capability so doesn’t happen again. Anyway I wave copied data from another My Cloud network drive to the new drive and unfortunately I have duplicate files and folders. I have tried to delete folder (using windows explorer, how I copied in first place) but keep getting do not have permission to move or delete, any ideas ?