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USB ports are slim rectangular openings with three-pronged symbols next to them. You'll typically find them on the sides of laptops' casings, though their locations vary for desktop computers.  If you can't find a USB port on your desktop computer, try looking at the sides or back of the keyboard, back of the CPU, or behind the desktop monitor. Some MacBooks don't have USB ports. The USB end of the charger is a rectangular piece of exposed metal; if you look at its end, you'll see a block of plastic inside. When plugging the cable into the USB port, make sure the three-pronged symbol on the USB cable is facing upward. You may need to disconnect the cable from the power adapter cube first. Do so by gently tugging on the USB end of the cable until it disengages from the power adapter. There are two types of charger cables for your iPhone and iPod:   Lightning - iPhone 5 and up; iPod touch 5th Generation and up. This cable's charging end is relatively narrow and flat.  30-pin - iPhone 4S and down; iPod touch 4th Generation and down. This cable's charging end is wide and flat. If you're using a Lightning cable, the charger should fit no matter how you insert it into the device's charging port; however, a 30-pin charger must be inserted with the grey rectangle icon on side of the charger facing the same way as the iPhone's screen. A second or so after plugging it in, your iPhone/iPod should make a sound (or vibrate), and the screen should briefly display a battery icon. If your device doesn't begin charging, try using a different electrical outlet.
Locate a USB port on your computer. Plug your iPhone or iPod cable into a USB port. Determine the type of charger cable you have. Insert the other end of the cable into the bottom of the device. Wait for your device to begin charging.