Range rover sport tv and stereo system questions

Hi I have a 57 reg rr sport hse tdv8, I have the original stereo sat nav tv but it does not show dvd can the sat nav dvd play dvd's or is it just for the sat nav? I also have the phone connection under the arm rest on top of the fridge is there any kind of aftermarket connection that can use this for anything like usb etc? or is there a usb connector i can buy for my existing stereo so i can watch films or play music from a memory stick? can a rev camra be plugged in to this stereo etc too?? I hope you can help

Im confused. You've already started a thread on this, with replies. Multiple threads just muddy the waters.
https://www.landyzone.co.uk/land-rover/im-back-rr-sport-tdv8-what-a-car.333603/