I'm laboring under the assumption the 2017 is like the 2013.
With the car in neutral, with ac outside vent set to recirculate then turned off and head lights in the off position>
> foot off the brake hold start button in UNTIL it says accessory position or something on. The door bells will chime while door is open. Close door and lock.
You should have a power wire from the coach to thee car. It will keep the battery charged and tail lights and turn signals/blinkers, brake lights working. If you see going into battery saving mode on the screen for GPS etc then you need to start over. Start car shift through geaars and park andbaack to neutral, with foot on brake of course. Cut the car off while in neutral and fooot on the brake.
Lift your foot from brake and don't put it back on and push the start keep until accessory position show on the little screen to the lef in our 2013 Edge, which normally shows door s open and so forth.
Door bell will chime with door open get out close door and lock.
Every eight hours I think it says stop and start the car and run it though the gears for five minuets or less.
When ever we stop we run it through the gears and repeat the procedure of course to put it in accessory mode.
Forget and leave it in park and you will get lovely black streaks as the car want's to stop. Then you will not go though the procedure a gain without co pilot doing the routine double check again.