Remote start install help


2016 Mazda 6 GT
Hey, I am new here and tried asking for help on one of the other Mazda forums without much luck. I noticed there isn't much traffic here on the Mazda 6 subforums, but maybe they are similar enough to the other models that someone can chime in. Let me know if I should post somewhere else.

I received a idatalink remote start module for Christmas. It is the DC3-LC model. I purchased the correct T-harness for it, and I have been searching for info on how to install it. I have done quite a bit with car stereo over the years, but this looks more complicated than I thought. My best buy in town said they would charge $150 to install it, and the guy wasn't too confidence inspiring for me.

Any advice or help?