Anyone figure out how to connect android phone to Kenwood car stereo???? Mine is the kmm bt315u

[AC Question]

Got a problem wondering if anyone else has figured this out yet or what. Can't connect my moto z droid to my new Kenwood kmm-bt315u stereo in USB or aux. One reason I can't in USB is I can't seem to find in my phone to change it from charging only to file transfer etc... If anyone could help me out that would be great! Being hooked up on Bluetooth for 3 hrs each is eating my data up!!! Burn through 8gb in a week! Thanks