I am trying to link my mobile phone into my car stereo system. It just repeats no phone when I try.

First not all phones will pair, you need to check if the phone you have is compatible, if yes and its still not pairing press the C/TA button several times before pressing the phone button. This should bring up the SIG message, then follow the manual's instructions.........

Chat is the C/TA button and where can I find it?