Just got my 2016 Subaru BRZ. Factory setting alarm is "off" Have followed instructions to "turn on alarm" - car not responding. Any suggestions please.

Sometimes worth following the instructions but if not then try different combinations of the procedures.
I had a Honda CRF1000 motorbike and couldn't reset the DCT, followed all the instructions then asked for help on a group and someone said - "you didn't have the side stand down?" - of course straight away it worked after that but just goes to show its sometimes the little things that need looking at.

Another example was Range Rover air suspension resets - it wouldn't work if any of the doors were open 😒