Attach a flash drive containing music files to your computer by inserting it into a USB port. If the computer asks what you'd like to do with the drive, simply close the window or select "Take no action."
Open iTunes. If you have a desktop icon, simply double-click it. If you don't, in Windows, use the following path to find and select the iTunes .exe file: From the Start menu, select "Programs" and then "iTunes." You also can go through My Computer, locate the Program Files folder, and find the iTunes .exe file that way.
Under the file menu in the main iTunes window, select "Add file to library" if you wish to import only one file. Select "Add folder to library" if you want to import an entire folder of music files.
A window will pop up when you select "Add file" or "Add folder." Using this window, navigate to your "My Computer" icon and double-click it so you can see all the drives associated with your computer (your flash drive will appear on this list).
Double-click on the flash drive.
Select the file or folder you wish to import and then click on "Open." Your music will be imported into iTunes.