This mp3 player could be charged derectly by the USB plug, you don't need to buy the extra charger.
After you preset a channel, please click the "menu" button, to" preset", to find "FM-/-", then you could preset the channel you like.
If you want delete, only need select the channel, then click the "menu" button, you could see "clear preset".
This mp3 player can be plugged directly into your car's stereo USB port to play songs or via the aux connection cable.
(Do not exclude that some older models are not compatible with the player)