I read someplace that there are 3 usb ports on the back of the radio unit that can be used for various purposes. Is it true that they exist? Would it be possible to use them in order to have a bluetooth connection for my phone to play music? How? If not, how can i put bluetooth to my car, for music via my phone, without installing an aftermarket navi or 12v socket modulator? Priority would be sound quality, if possible. Thanks.

What radio model is installed? I don't recall any model with three type A usb ports.

In my car with a Bolero radio I can plug a Bluetooth receiver into the AUX socket in the central armrest/cubby hole, then set the radio to AUX.

No good for phone conversations but can play anything stored on your phone. Music sounds no different to same tune played on the SD card on the front of the radio.

I have the default unit. This one

I see you have a late Stream model.

Go to the pinned handbook posts above and look for your year and model. You should see a link to the handbook for your radio.