Blue tooth phone connection

[The Merle]

I was wondering if anyone can help, I've just bought an newer Cali 4motion and it has a rns300 stereo and can't workout or seem to link my iPhone with the blue tooth connection on the stereo!!
Unfornately the instruction book was missing
Also looking to upgrade unit to kenwood rns510 is it worth the £1150 cost, is the satnav any good for Europe (does it have overhead gantries signage on satnav?) also does it have full iPod/iPhone controls charging etc.
One last one is the dab any good in UK and Europe or does it drop out a lot?
Thanks