Transferring iTunes to a USB stick

I recently purchased a car that holds 7000 songs that can be downloaded from a USB stick. I tried copying some of my iTunes to load to the car but it did not work. The method I used was to select the songs in iTunes library, copy and then paste to the USB stick. When I connected the stick to my car I got a message stating that there was no information on the stick.
Can anyone give me some ideas on how to get my iTunes transferred?