Bluetooth relemetry setup

Hi there,
i am trying to use bluetooth module for telem1 port, bec i want to control copter via another device with bluetooth HC08. but i am quite new here, and i have troule finding what code to modify. For example, what codes are in charge of reading data from telem1 port and how it outputs to motors. Just give me some hints and files to pay attention to.
THANK YOU VERY MUCH!

Andy