That manual is for the 2016 Pinnacle which has a different model refrigerator. I also have a 2015 Pinnacle. I haven't winterized the refrigerator yet, but here is hoe I think it will have to be done. There is a test button on the bottom front of the ice maker. As you are blowing air or adding antifreeze you will have to continually push the test button until you only air, not any water come out; or until antifreeze starts to load into the ice tray. Be sure to remove and wipe antifreeze from the tray and any other plastic parts as it will stain the plastic.
I have an appointment with my dealer in earlier August and I will confirm this with them. I will report here if there is any different procedure.