Does the 2008 Mazda3 (imported) 1.6L automatic version without a central control screen use a USB drive or CDs for playing music?

The 2008 imported Mazda3 hatchback comes with a six-disc CD changer.

I upgraded my Bluetooth. Can anyone recommend posts to read?

This 2008 model doesn't come with a multimedia system; it only has a simple radio function and doesn't support discs. Typically, you'll need to upgrade it later to replace it with a large screen.

If you want to listen to music in this car, you'll need a CD. Alternatively, you can use an aux cable. You can buy one yourself, and connect an old MP3 player to the aux input, and that will work for playing music too.