Music from You Tube

Not sure how to ask this but here goes. I am a senior not that great with my Desktop PC. I happened to go to youtube the other day. I found music that I enjoy to listen too. I bought a couple of USB 64 GB not sure how many songs you can place on a USB. This is called a Cruzer Glide USB Flash Drive.
I am listing to a unit that has a bunch of really nice songs that I like. I inserted the USB into my tower hoping that I would be able to play the USB in my Vehicle as I am driving. But nothing happened. do you have to download a USB on a computer first or what? can you help with this? Is there a real step by step on exactly what to do and see what each step will look like before I would click on it. If there is such a thing as that I think it would help me a lot. I would first print the instructions and then follow exactly what it says to do for each part. Thank You. Hope to hear from you.Nelson